Question

Out of three numbers, the first is twice the second and is half of the third. If the average of three numbers is $56,$ then the difference of the first and third is

• A. $12$
• B. $20$
• C. $24$
• D. $48$

Answer 1

The correct option is D $48$

Let the first number be $x$ and $y$ be the second number and $z$ be the third number

given that, x = 2.y and x = z/2

Then, Second number(y) = $\frac{x}{2}$
Third number(z) $=2x$

Given, $\frac{x+\frac{x}{2}+2x}{3}=56\Rightarrow \frac{7x}{6}=56\Rightarrow x=\frac{56\times 6}{7}48$

$\therefore$ Difference between first and third $=2x-x=x=48$.