The compound interest on ₹1,400 for 18 months at the rate of 20% per annum is:

Correct option is C

Given:

Principal (P) = ₹1,400

Time (T) = 18 months = 1.5 years

Rate (R) = 20% per annum

Formula Used:

For 1.5 year CI:

Amount, A = $$P \left(1 + \frac{R}{100}\right)^n \left(1+\frac{R/2}{100}\right)$$​​

Total CI = Final Amount - Principal

Solution:

Amount after 1.5 year (CI):

​$$A = 1400 \left(1 + \frac{20}{100}\right)^1\left(1+\frac{20/2}{100}\right) \\ \ \\A = 1400 \left(\frac{120}{100}\right)\left(\frac{110}{100}\right)^{1}\\ \ \\ A = 1400 \times \frac{6}{5}\times \frac{11}{10} \\ \ \\A = 28 \times 6 \times 11 \\ \ \\ A = ₹1848$$​​

Total Compound Interest(CI) = ₹1,848 - ₹1,400 = ₹448