1. Let, the lenght of hall = l m, breadth = b m and height = h m Permeter of floor = 2(l + b) According of question, 2(l + b) = 250 m ...(1) Area of four walls of hall = 2(l + b) h So, the cost of painting the four walls at the rate of Rs 10 per m² = 2(l + b) h × Rs 10 = 250h × Rs 10 [∵ From equation (Read more

    Let, the lenght of hall = l m, breadth = b m and height = h m
    Permeter of floor = 2(l + b)
    According of question, 2(l + b) = 250 m …(1)
    Area of four walls of hall = 2(l + b) h
    So, the cost of painting the four walls at the rate of Rs 10 per m² = 2(l + b) h × Rs 10
    = 250h × Rs 10 [∵ From equation (1)]
    = Rs 2500h
    According to question, Rs 2500h = 15000
    ⇒ h = 15000/2500 = 6 m
    Hence, the height of the hall is 6 m.

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  2. Lenght of one brick l = 22.5 cm, breadth b = 10 cm and height h = 7.5 cm Total surface area of brick = 2(lb + bh + hl) = 2(22.5 × 10 + 10 × 7.5 + 7.5 × 22.5) cm² = 2(225 + 75 + 168.75) cm² = 937.5 cm² = 0.09375 m² Number of bricks to be painted = Total paint available/paint for one brick = 9.375 m²/Read more

    Lenght of one brick l = 22.5 cm, breadth b = 10 cm and height h = 7.5 cm
    Total surface area of brick = 2(lb + bh + hl) = 2(22.5 × 10 + 10 × 7.5 + 7.5 × 22.5) cm²
    = 2(225 + 75 + 168.75) cm² = 937.5 cm² = 0.09375 m²
    Number of bricks to be painted
    = Total paint available/paint for one brick = 9.375 m²/0.09375 m² = 100
    Hence, the paint of this container can paint 100 bricks.

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  3. Five examples of data that we can collect from our day-to-day life. 1. Height of our classmates or weight of our classmate. 2. Height of first 100 plants near by our locality. 3. Maximum or minimum temperature of a particular month. 4. Time spend for watching TV in a particular week. 5. Rainfall inRead more

    Five examples of data that we can collect from our day-to-day life.
    1. Height of our classmates or weight of our classmate.
    2. Height of first 100 plants near by our locality.
    3. Maximum or minimum temperature of a particular month.
    4. Time spend for watching TV in a particular week.
    5. Rainfall in our city in last 10 years.

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  4. Total number of balls = 30 Number of balls having boundary = 6 Therefore, the number of balls not having boundary = 30 - 6 = 24 P (she did not hit a boundary) = 24/30 = 4/5 = 0.8 Hence, the probability of not hitting a boundary by her is 0.8.

    Total number of balls = 30
    Number of balls having boundary = 6
    Therefore, the number of balls not having boundary = 30 – 6 = 24
    P (she did not hit a boundary) = 24/30 = 4/5 = 0.8
    Hence, the probability of not hitting a boundary by her is 0.8.

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  5. Example 5, section 14.4, chapter 14 is given below: In a particular section of class ix, 40 students were asked about the months of their birth and the following graph was prepared for the data so obtained: Total number of student = 40 Number of students born in August = 6 Therefore, p(Student bornRead more

    Example 5, section 14.4, chapter 14 is given below:
    In a particular section of class ix, 40 students were asked about the months of their birth and the following graph was prepared for the data so obtained:
    Total number of student = 40
    Number of students born in August = 6
    Therefore,
    p(Student born in August) = 6/40 = 3/20
    Hence, the probability that the student born in August is 3/20.

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