Question

The sum of squares of two number is 13 and their product is 3. Find the sum of the two numbers.

• A. 6
• B. 4
• C. 3
• D. 5

Answer 1

The correct option is B 4

Let the two numbers be x and y.
The sum of squares of two number is 13,
$\Rightarrow x^2+y^2=13$ --- (1)
The product of two number = 3
$\Rightarrow xy=6$ ---- (2)
Using the identity $(a+b{)}^2=a^2+b^2+2ab$,
$\Rightarrow (x+y{)}^2=x^2+y^2+2xy$
$\Rightarrow (x+y{)}^2=13+3=16$
$\Rightarrow (x+y)=4$
Hence, Sum of the numbers = 4.