Question 809278
Calculate the interest accrued in 8 years when the oldest becomes 25

Some how you have to know what amount the sons will receive and subtract that from the new principal.
then calculate interest accrued after 5 more years when the middle son turns 25
again with magic subtract the same amount from the amount accrued.
and finally calculate the amount accrued n 4 more years and distribute it.
perhaps the approach should be start at the end.