(a) Haziq invests RM15,000 in a fund at 7% compounded quarterly. After t years, the value of the investment is RM300,000. Determine the value of t.
(b) Sarah invested RM5000 into an account that pays 5% compounded semiannually. She intended to keep the account untouched for 5 years. However, after 3 years, she had to withdraw RM3000. Find the amount left in the account after five years from the time she made her investment.