Question

The compound interest on a certain sum at a certain rate percent per annum for the second year and the third year are ₹ 3300 and ₹ 3630, respectively. The sum is:

• A. ₹ 32000
• B. ₹ 28400
• C. ₹ 30000
• D. ₹ 25000

Answer 1

Answer:

C. ₹ 30000

Solution:

GIVEN:

CI for 3 years = ₹ 3630

CI for 2 years = ₹ 3300

FORMULAE USED:

Interest rate = [(CI_3year – CI_2year)/CI2year] × 100

CALCULATION:

Interest rate = [(3630 – 3300)/3300] × 100 = 10%

CI for first year = $3300\times{\frac{100}{110}} = 3000$

Let Principal be P, then

10 % of P = 3000

$P\times{\frac{1}{10}} = 3000$

P = ₹ 30,000