

Given sum = 10000
Rate of interest = 5%
Now amount in 15th year = 10000 + SI for 15 years
= 10000 + (10000*5*15)/100
= 10000 + 100*75
= 10000 + 7500
= 17500
2. Now amount after 20 years = 10000 + (10000*5*20)/100
= 10000 + 100*100
= 10000 + 10000
= 20000
