Question

The compound interest on a certain sum at a certain rate percent per annum for the second year and the third year are Rs. 1,650 and Rs. 1,815, respectively. The sum and the rate of interest are respectively
1. Rs. 12,000 and 10%
2. Rs. 15,000 and 10%
3. Rs. 16,000 and 8%
4. Rs. 12,000 and 12%

Answer 1

Correct Answer - Option 2 : Rs. 15,000 and 10%

Given:

Interest for the second year is 1650 and interest for the third year is 1815

Concept:

Compound interest = P × {(1 + R/100)^T - 1}, Where P = Principle, R = Rate, T = Time

Calculation:

Let be assume principle is P

⇒ 1650 = P × {(1 + R/100)² - 1} ...... (1)

⇒ 1815 = P × {(1 + R/100)³ - 1} ..... (2)

⇒ By dividing the equation (1) and (2)

⇒ R = 10%

⇒ From equation (1)

⇒ P = 15000

∴ The required result will be "15000, 10%"