A positive number is 5 times another number. If 21 is added to both the numbers, then one of the new numbers becomes twice the other new number. What are the numbers?

Let another number be x.
Then positive number = 5x
According to the question, 5x+21=2(x+21)
⇒ 5x+21=2x+42 ⇒ 5x-2x=42-21 ⇒ 3x=21
⇒ x=21/3=7
Hence another number = 7 and positive number = 5×7=35

Class 8 Maths Chapter 2 Exercise 2.4 Solution in Video

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