Discussion Forum



1)

The sum of two numbers is 25 and their difference is 13. B'ind their product.


A) 104

B) 114

C) 315

D) 325

E) 350

Answer:

Option B

Explanation:

Let the numbers be $x$ and $y$. Then,
$x+y=25$ and $x-y=13$.
$4xy=(x+y)^{2}-(x-y)^{2}$
$=(25)^{2}-(13)^{2}=625-139=456$
$\Rightarrow xy = 114$.