Question

If the sum of $2$ real numbers is $20$ and their difference is $6$, find the value of their product.

• A. $51$
• B. $64$
• C. $75$
• D. $84$
• E. $91$

Answer 1

Answer: (E)

$91$

Let the two numbers are $x$ and $y$

Then according to the question,

$\Rightarrow x+y=20...\left(1\right)$

$\Rightarrow x-y=6...\left(2\right)$

Add $\left(1\right)$ and $\left(2\right)$, we get

$\Rightarrow 2x=26$

$\Rightarrow x=\frac{26}{2}=13$

Put the value of $x$ in $\left(1\right)$

$\Rightarrow 13+y=20$

$\Rightarrow y=20-13=7$

Product of $x$ and $y=$ $x\times y=13\times 7=91$