Question

Evaluate the following.

\(\frac{(12.5)^3 + (7.5)^3}{(12.5)^2 + (7.5)^2 - 12.5 \times 7.5}\)

1. 25
2. 30
3. 20
4. 15

Answer 1

Correct Answer - Option 3 : 20

Formula used :

A³ + B³ = (A + B)(A² + B² - AB)

Calculations :

\(\frac{(12.5)^3 + (7.5)^3}{(12.5)^2 + (7.5)^2 - 12.5 \times 7.5}\)

⇒ \(\frac{(12.5 + 7.5)[(12.5)^2 + (7.5)^2 - (12.5 × 7.5)]}{(12.5)^2 + (7.5)^2 - 12.5 \times 7.5}\)

⇒ 12.5 + 7.5 

⇒ 20

∴ Option 3 will be the correct answer.