A sum of Rs.4,000 becomes Rs.4,960 in 4 year at sin1ple interest. If the rate of interest becomes 1.5 times of itself, then bow much this sum will become after 4 years?

Rs.5,440

Simple Interest = \(\frac{Principal ×Rate × Time }{100}\)

Amount = Principal + Interest

Simple interest in 4 years = 4960 - 4000 = 960

Now ,

960 = \(\frac{40000 × Rate × 4 }{100}\)

Rate of interest per year = \(\frac{960 × 100 }{4000×4}\)

= \(\frac{96  }{4×4}\)

= 6%

New rate = 1.5 × Old rate = 1.5 × 6 = 9%

New simple interest for 4 years = \(\frac{4000×9 × 4 }{100}\) = Rs. 1440

New amount after 4 years = 4000 + 1440 = Rs. 5440