# What Least Number Must Be Subtracted from Each of the Numbers 7, 17 and 47 So that the Remainders Are in Continued Proportion? - Mathematics

Sum

What least number be subtracted from each of the numbers 7, 17 and 47 so that the remainders are in continued proportion?

#### Solution

Let the number subtracted be x

∴ (7 - x) : (17 - x) :: (17 - x)(47 - x)

(7 - x)/(47 - x) = (17 - x)^2

329 - 47x - 7x + x^2 = 289 - 34x = x^2

329 - 289 = -34x + 54x

20x = 40

x = 2

Thus the required number which should be subtracted is 2

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#### APPEARS IN

Selina Concise Maths Class 10 ICSE
Chapter 7 Ratio and Proportion (Including Properties and Uses)
Exercise 7 (B) | Q 8 | Page 94