On simple interest, a certain sum becomes ₹59,200 in 6

Solution

On simple interest, a certain sum becomes Rs. 59,200 in 6 years and Rs. 72,000 in 10 years. The total interest in 4 years = 72000 - 59200 = Rs. 12800 The total interest in 6 years = (12800/4) × 6 = Rs. 19200 So, the total amount = 59200 - 19200 = Rs. 40000 The rate of interest had been 2% more 40000 × (2/100) = Rs. 800 The new total interest in 1 year = (12800/4) + 800 = Rs. 4000 The required interest = 76000 - 40000 = Rs. 36000 So, the time required = 36000/4000 = 9 years ∴ The sum have become RS. 76,000 in 9 years