₹6000 becomes ₹7200 in 3 years at a certain rate of compound interest. What will be the amount received after 9 years?

Rs 6000 becomes Rs 7200 in 4 years at a certain rate of simple interest. If the rate becomes 1.5 times of itself, the amount of the same principal in 5 years will be (a) Rs 8000 (b) Rs 8250 (c) Rs 9000 (d) Rs 9250

2400 becomes 2976 in 3 years at a certain rate of simple interest. What sum of money will become 5016 in 4 years at the same rate of interest?