Question

Two number differ by 5. If their product is 336, then the sum of the two numbers is :

• A. $21$
• B. $28$
• C. $37$
• D. $51$

Answer 1

Answer: (C)

$37$

Let numbers are x and y

$\Rightarrow x-y=5$

$xy=336$

Now using identity

$(x+y{)}^2=(x-y{)}^2+4xy$

$=25+4\left(336\right)$

$=25+1344$

$=1369$

$\Rightarrow x+y=37$