Correct Answer - Option 2 : Rs.180
Given:
Amar borrowed 2000 Rs. at 30% per annum simple interest and then immediately lent in at 30% per annum compound interest
Formula used:
SI = \(\dfrac{P \times R \times T}{100}\)
Amount = P(1 + \(\dfrac{R}{100}\))T
P = principal
R = rate of interest
T = time period
Calculation:
SI on 2000 at 30% per annum = \(\dfrac{2000 \times 30 \times 2}{100}\) = 1200
CI on 2000 at 30% per annum for 2 years = Amount - Principal
⇒ CI = 2000(1 + \(\dfrac{30}{100}\))2 - 2000
⇒ CI = 2000[(169/100) - 1]
⇒ CI = 2000(69/100)
⇒ CI = 1380
CI - SI = 1380 - 1200 = 180
∴ His gain = Rs. 180