The sum of two numbers is 25 and their difference is 13. Find their product. · ABC26GN1688
Subject: General Aptitude · Chapter: Problems on Numbers
The sum of two numbers is 25 and their difference is 13. Find their product.
(a)104
(b)114
(c)315
(d)325
Answer
Answer (as printed): B
Explanation
Let the numbers be $x$ and $y$. Then, $x+y=25$ and $x-y=13$. $$\begin{aligned} 4 x y & =(x+y)^{2}-(x-y)^{2}=(25)^{2}-(13)^{2} \\ & =625-169=456 \Rightarrow x y=114 . \end{aligned}$$
Explanation as extracted from the printed page; notation may be imperfect.