Starting position of mine shaft is 10 m above the ground but it moves in opposite direction so it travels the distance (–350) m below the ground. So total distance covered by mine shaft = 10 m – (–350) m = 10 + 350 = 360 m Now, time taken to cover a distance of 6 m by it = 1 minute So, time taken toRead more
Starting position of mine shaft is 10 m above the ground but it moves in opposite
direction so it travels the distance (–350) m below the ground.
So total distance covered by mine shaft = 10 m – (–350) m = 10 + 350 = 360 m
Now, time taken to cover a distance of 6 m by it = 1 minute
So, time taken to cover a distance of 1 m by it = 1/6 minute
Therefore, time taken to cover a distance of 360 m = 1/6×360
= 60 minutes = 1 hour
(Since 60 minutes = 1 hour)
Thus, in one hour the mine shaft reaches –350 below the ground.
(i) Marks given for one correct answer = 3 Marks given for 12 correct answers = 3 x 12 = 36 Radhika scored 20 marks. Therefore, Marks obtained for incorrect answers = 20 – 36 = –16 Now, marks given for one incorrect answer = –2 Therefore, number of incorrect answers = (-16) ÷(-2) = 8 Thus, Radhika hRead more
(i) Marks given for one correct answer = 3
Marks given for 12 correct answers = 3 x 12 = 36
Radhika scored 20 marks.
Therefore, Marks obtained for incorrect answers = 20 – 36 = –16
Now, marks given for one incorrect answer = –2
Therefore, number of incorrect answers = (-16) ÷(-2) = 8
Thus, Radhika has attempted 8 incorrect questions.
(ii) Marks given for seven correct answers = 3 x 7 = 21
Mohini scores = –5
Marks obtained for incorrect answers = = –5 – 21 = –26
Now, marks given for one incorrect answer = –2
Therefore, number of incorrect answers = (-26) ÷ (-2) = 13
Thus, Mohini has attempted 13 incorrect questions.
Given: a ÷(b+c) ≠ (a÷b) + (a÷c) a=12, b = -4, c=2 Putting the given values in L.H.S. = 12÷(-4+2) = 12÷(-2) = 12÷(-1/2) = -12/2 =-6 Putting the given values in R.H.S. = [12÷(-4)]+(12÷2) = (12x-1/4)+6=-3+6=3 Since, L.H.S. ≠ R.H.S. Hence verified. Exercise 1.4 Question 2, 3, 4, 5 for more answers vistRead more
Given: a ÷(b+c) ≠ (a÷b) + (a÷c)
a=12, b = -4, c=2
Putting the given values in L.H.S. = 12÷(-4+2)
= 12÷(-2) = 12÷(-1/2) = -12/2 =-6
Putting the given values in R.H.S. = [12÷(-4)]+(12÷2)
= (12x-1/4)+6=-3+6=3
Since, L.H.S. ≠ R.H.S.
Hence verified.
(-30) ÷10 = (-30)x1/10 = -30x1/10 = -3 Exercise 1.4 Question 1 for more answers vist to: https://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
(-3) x (-9) = 27 Class 7 Maths Exercise 1.3 Questions 6, 7, 8, 9 for more answers vist to: https://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
Given: Profit of 1 bag of white cement = ₹ 8 And Loss of 1 bag of grey cement = ₹ 5 (a) Profit on selling 3000 bags of white cement = 3000 x ₹ 8 = ₹ 24,000 Loss of selling 5000 bags of grey cement = 5000 x ₹ 5 = ₹ 25,000 Since Profit < Loss Therefore, his total loss on selling the grey cement bagRead more
Given: Profit of 1 bag of white cement = ₹ 8
And Loss of 1 bag of grey cement = ₹ 5
(a) Profit on selling 3000 bags of white cement = 3000 x ₹ 8 = ₹ 24,000
Loss of selling 5000 bags of grey cement = 5000 x ₹ 5 = ₹ 25,000
Since Profit < Loss
Therefore, his total loss on selling the grey cement bags = Loss – Profit
= ₹ 25,000 – ₹ 24,000
= ₹ 1,000
Thus, he has lost of `₹1,000 on selling the grey cement bags.
(b) Let the number of bags of white cement be x.
According to question, Loss = Profit
∴ 5 x 6,400 = x X 8
⇒ x = 5×6400/8 = 5000 bags
Thus, he must sell 4000 white cement bags to have neither profit nor loss.
(i) Mohan gets marks for four correct questions = 4 x 5 = 20 He gets marks for six incorrect questions = 6 x (–2) = –12 Therefore, total scores of Mohan = (4 x 5) + [6 x (–2)] = 20 – 12 = 8 Thus, Mohan gets 8 marks in a class test. (ii) Reshma gets marks for five correct questions = 5 x 5 = 25 She gRead more
(i) Mohan gets marks for four correct questions = 4 x 5 = 20
He gets marks for six incorrect questions = 6 x (–2) = –12
Therefore, total scores of Mohan = (4 x 5) + [6 x (–2)]
= 20 – 12 = 8
Thus, Mohan gets 8 marks in a class test.
(ii) Reshma gets marks for five correct questions = 5 x 5 = 25
She gets marks for five incorrect questions = 5 x (–2) = –10
Therefore, total score of Resham = 25 + (–10) = 15
Thus, Reshma gets 15 marks in a class test.
(iii) Heena gets marks for two correct questions = 2 x 5 = 10
She gets marks for five incorrect questions = 5 x (–2) = –10
Therefore, total score of Resham = 10 + (–10) = 0
Thus, Reshma gets 0 marks in a class test.
Given: Present room temperature = 40°C Decreasing the temperature every hour = 5°C Room temperature after 10 hours = 40°C + 10 x (–5°C ) = 40°C – 50°C = – 10°C Thus, the room temperature after 10 hours is – 10°C after the process begins. Class 7 Maths Exercise 1.3 Questions 6, 7, 8, 9 for more answeRead more
Given: Present room temperature = 40°C
Decreasing the temperature every hour = 5°C
Room temperature after 10 hours = 40°C + 10 x (–5°C )
= 40°C – 50°C
= – 10°C
Thus, the room temperature after 10 hours is – 10°C after the process begins.
An elevator descends into a mine shaft at the rate of 6 m/min. If the descent starts from 10 above the ground level, how long will it take to reach -350 m?
Starting position of mine shaft is 10 m above the ground but it moves in opposite direction so it travels the distance (–350) m below the ground. So total distance covered by mine shaft = 10 m – (–350) m = 10 + 350 = 360 m Now, time taken to cover a distance of 6 m by it = 1 minute So, time taken toRead more
Starting position of mine shaft is 10 m above the ground but it moves in opposite
direction so it travels the distance (–350) m below the ground.
So total distance covered by mine shaft = 10 m – (–350) m = 10 + 350 = 360 m
Now, time taken to cover a distance of 6 m by it = 1 minute
So, time taken to cover a distance of 1 m by it = 1/6 minute
Therefore, time taken to cover a distance of 360 m = 1/6×360
= 60 minutes = 1 hour
(Since 60 minutes = 1 hour)
Thus, in one hour the mine shaft reaches –350 below the ground.
Exercise 1.4 Question 6, 7
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
In a class test (+3) marks are given for every correct answer and (-2) marks are given for every incorrect answer and no marks for not attempting any question. (i) Radhika scored 20 marks. If she has got 12 correct answers, how many questions has she attempted incorrectly? (ii) Mohini scores (-5) marks in this test, though she has got 7 correct answers. How many questions has she attempted incorrectly?
(i) Marks given for one correct answer = 3 Marks given for 12 correct answers = 3 x 12 = 36 Radhika scored 20 marks. Therefore, Marks obtained for incorrect answers = 20 – 36 = –16 Now, marks given for one incorrect answer = –2 Therefore, number of incorrect answers = (-16) ÷(-2) = 8 Thus, Radhika hRead more
(i) Marks given for one correct answer = 3
Marks given for 12 correct answers = 3 x 12 = 36
Radhika scored 20 marks.
Therefore, Marks obtained for incorrect answers = 20 – 36 = –16
Now, marks given for one incorrect answer = –2
Therefore, number of incorrect answers = (-16) ÷(-2) = 8
Thus, Radhika has attempted 8 incorrect questions.
(ii) Marks given for seven correct answers = 3 x 7 = 21
Mohini scores = –5
Marks obtained for incorrect answers = = –5 – 21 = –26
Now, marks given for one incorrect answer = –2
Therefore, number of incorrect answers = (-26) ÷ (-2) = 13
Thus, Mohini has attempted 13 incorrect questions.
Exercise 1.4 Question 6, 7
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
Write five pairs of integers (a,b) such that a÷b= -3.One such pair is (6,-2) because 6 ÷(-2) = (-3).
(i) (-6)÷2 = -3 (ii) 9÷(-3) = -3 (iii) 12÷(-4) = -3 (iv) (-9)÷3 = -3 (v) (-15)÷5=-3 Exercise 1.4 Question 2, 3, 4, 5 for more answers vist to: https://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
(i) (-6)÷2 = -3
(ii) 9÷(-3) = -3
(iii) 12÷(-4) = -3
(iv) (-9)÷3 = -3
(v) (-15)÷5=-3
Exercise 1.4 Question 2, 3, 4, 5
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
Fill in the blanks: 369 ÷ ………….. = 369
369 ÷ 1 = 369 Exercise 1.4 Question 2, 3, 4, 5 for more answers vist to: https://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
369 ÷ 1 = 369
Exercise 1.4 Question 2, 3, 4, 5
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
Verify that a ÷(b+c) ≠ (a÷b) + (a÷c) for each of the following values of and ,ab . c (a) a=12, b = -4, c=2
Given: a ÷(b+c) ≠ (a÷b) + (a÷c) a=12, b = -4, c=2 Putting the given values in L.H.S. = 12÷(-4+2) = 12÷(-2) = 12÷(-1/2) = -12/2 =-6 Putting the given values in R.H.S. = [12÷(-4)]+(12÷2) = (12x-1/4)+6=-3+6=3 Since, L.H.S. ≠ R.H.S. Hence verified. Exercise 1.4 Question 2, 3, 4, 5 for more answers vistRead more
Given: a ÷(b+c) ≠ (a÷b) + (a÷c)
a=12, b = -4, c=2
Putting the given values in L.H.S. = 12÷(-4+2)
= 12÷(-2) = 12÷(-1/2) = -12/2 =-6
Putting the given values in R.H.S. = [12÷(-4)]+(12÷2)
= (12x-1/4)+6=-3+6=3
Since, L.H.S. ≠ R.H.S.
Hence verified.
Exercise 1.4 Question 2, 3, 4, 5
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
Evaluate each of the following: (-30) ÷10
(-30) ÷10 = (-30)x1/10 = -30x1/10 = -3 Exercise 1.4 Question 1 for more answers vist to: https://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
(-30) ÷10 = (-30)x1/10 = -30×1/10 = -3
Exercise 1.4 Question 1
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
Replace the blank with an integer to make it a true statement: (-3) x……. = 27
(-3) x (-9) = 27 Class 7 Maths Exercise 1.3 Questions 6, 7, 8, 9 for more answers vist to: https://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
(-3) x (-9) = 27
Class 7 Maths Exercise 1.3 Questions 6, 7, 8, 9
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
A cement company earns a profit of ₹8 per bag of white cement sold and a loss of ₹ 5 per bag of grey cement sold. (a) The company sells 3,000 bags of white cement and 5,000 bags of grey cement in a month. What is its profit or loss? (b) What is the number of white cement bags it must sell to have neither profit nor loss. If the number of grey bags sold is 6,400 bags.
Given: Profit of 1 bag of white cement = ₹ 8 And Loss of 1 bag of grey cement = ₹ 5 (a) Profit on selling 3000 bags of white cement = 3000 x ₹ 8 = ₹ 24,000 Loss of selling 5000 bags of grey cement = 5000 x ₹ 5 = ₹ 25,000 Since Profit < Loss Therefore, his total loss on selling the grey cement bagRead more
Given: Profit of 1 bag of white cement = ₹ 8
And Loss of 1 bag of grey cement = ₹ 5
(a) Profit on selling 3000 bags of white cement = 3000 x ₹ 8 = ₹ 24,000
Loss of selling 5000 bags of grey cement = 5000 x ₹ 5 = ₹ 25,000
Since Profit < Loss
Therefore, his total loss on selling the grey cement bags = Loss – Profit
= ₹ 25,000 – ₹ 24,000
= ₹ 1,000
Thus, he has lost of `₹1,000 on selling the grey cement bags.
(b) Let the number of bags of white cement be x.
According to question, Loss = Profit
∴ 5 x 6,400 = x X 8
⇒ x = 5×6400/8 = 5000 bags
Thus, he must sell 4000 white cement bags to have neither profit nor loss.
Class 7 Maths Exercise 1.3 Questions 6, 7, 8, 9
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
In a class test containing 10 questions, 5 marks are awarded for every correct answer and (-2) marks are awarded for every incorrect answer and 0 for questions not attempted. (i) Mohan gets four correct and six incorrect answers. What is his score? (ii) Reshma gets five correct answers and five incorrect answers, what is her score? (iii) Heena gets two correct and five incorrect answers out of seven questions she attempts. What is her score?
(i) Mohan gets marks for four correct questions = 4 x 5 = 20 He gets marks for six incorrect questions = 6 x (–2) = –12 Therefore, total scores of Mohan = (4 x 5) + [6 x (–2)] = 20 – 12 = 8 Thus, Mohan gets 8 marks in a class test. (ii) Reshma gets marks for five correct questions = 5 x 5 = 25 She gRead more
(i) Mohan gets marks for four correct questions = 4 x 5 = 20
He gets marks for six incorrect questions = 6 x (–2) = –12
Therefore, total scores of Mohan = (4 x 5) + [6 x (–2)]
= 20 – 12 = 8
Thus, Mohan gets 8 marks in a class test.
(ii) Reshma gets marks for five correct questions = 5 x 5 = 25
She gets marks for five incorrect questions = 5 x (–2) = –10
Therefore, total score of Resham = 25 + (–10) = 15
Thus, Reshma gets 15 marks in a class test.
(iii) Heena gets marks for two correct questions = 2 x 5 = 10
She gets marks for five incorrect questions = 5 x (–2) = –10
Therefore, total score of Resham = 10 + (–10) = 0
Thus, Reshma gets 0 marks in a class test.
Class 7 Maths Exercise 1.3 Questions 6, 7, 8, 9
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/
A certain freezing process requires that room temperature be lowered from 40° C at the rate of 5°C every hour. What will be the room temperature 10 hours after the process begins?
Given: Present room temperature = 40°C Decreasing the temperature every hour = 5°C Room temperature after 10 hours = 40°C + 10 x (–5°C ) = 40°C – 50°C = – 10°C Thus, the room temperature after 10 hours is – 10°C after the process begins. Class 7 Maths Exercise 1.3 Questions 6, 7, 8, 9 for more answeRead more
Given: Present room temperature = 40°C
Decreasing the temperature every hour = 5°C
Room temperature after 10 hours = 40°C + 10 x (–5°C )
= 40°C – 50°C
= – 10°C
Thus, the room temperature after 10 hours is – 10°C after the process begins.
Class 7 Maths Exercise 1.3 Questions 6, 7, 8, 9
for more answers vist to:
See lesshttps://www.tiwariacademy.com/ncert-solutions/class-7/maths/chapter-1/