Two numbers are such that their product is equal to 21 and the sum of their squares is 58. Find the difference between the two numbers.

A4 ✓ Correct

Correct answer: (A) 4

Explanation

The difference is 4.

Use (a - b)^2 = a^2 + b^2 - 2ab.

Here a^2 + b^2 = 58 and ab = 21.

So (a - b)^2 = 58 - 2 x 21 = 58 - 42 = 16.

Difference = root(16) = 4.

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