Aptitude - Problems on Numbers - Discussion

Discussion Forum : Problems on Numbers - General Questions (Q.No. 12)
12.
The product of two numbers is 120 and the sum of their squares is 289. The sum of the number is:
20
23
169
None of these
Answer: Option
Explanation:

Let the numbers be x and y.

Then, xy = 120 and x2 + y2 = 289.

(x + y)2 = x2 + y2 + 2xy = 289 + (2 x 120) = 529

x + y = 529 = 23.

Discussion:
12 comments Page 2 of 2.

Pavan said:   1 decade ago
@Abishek.

In this question we already know their products and sum of the squares of their products only one we have to find out is their sum. So here we are using (a+b)whole square formulae:

Hence we are adding 289+2(120).

Argghx said:   2 months ago
A^2+b^2=289 a*b=120apply (a+b) ^2 formula and replace the value.

If you are thinking square rooting 289 and getting a+b = 17 is right,

Here it doesn't satisfy thee first case of a*b=120.


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