Age Loan Amount Government Grant (20%) Total Interest in 4yr Net Gain
13 5000 1000 17x48 = 816 1000 - 816 = 184
14 5000 1000 17x36 = 612 1000 - 612 = 388
15 5000 1000 17x24 = 408 1000 - 408 = 592
16 5000 1000 17x12 = 204 1000 - 204 = 796
17 5000 1000 17x0 = 0 1000 - 0 = 1000
 
Total net gain     = 2960

If your investment grows at per annum, your total gain is - (25000 + 2040) =

Disclaimer: Rate of return are not guranteed. It is only for assumption purposes. Actual value can fluctuate.