IIMB 2001 (QA) PYQs

Naruto left a will of 3.5 million ryō (currency) to be distributed among his heirs, Boruto (Age: 16) and Himawari (Age: 8.5), ensuring they each get equal amounts when they turn 21. The amount is to be invested at 10% p.a. simple interest. How much percentage of the 3.5 million ryō would Boruto receive at the time of the will?

Raj borrows Rs. $1500$ at $5\%$ compound rate of interest. At the end of each year, he pays back Rs. $500$. How much amount should he pay at the end of the third year to clear all his dues?(approximately)

The difference between Compound Interest and Simple Interest on some principal amount at $10\%$ per annum for $3$ years is Rs. $31$ then find the principal