Of three numbers, average of first and second is greater than average of second and third by 15 . di

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4.Average

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Of the three numbers, the average of the first and the second is greater than the average of the second and the third by $15 .$ What is the difference between the first and the third of the three numbers?

A

$15$

B

$45$

C

$60$

D

$30$

Solution

Let $x, y$ and $z$ be the numbers.

$\frac{x+y}{2}=\frac{y+z}{2}+15$

$\frac{x-z}{2}=15$

$x-z=2 \times 15=30$

Standard 13

Quantitative Aptitude

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