Steven lent $5,700 at 4% p

Steven lent $5,700 at 4% p.a. on March 27, 2014. Calculate the amount of interest she should receive if the loan extends until February 18, 2015
Zachary invested $207 for 21 months in a bank and received a maturity amount of $224.50. If she had invested the amount in a fund earning 3.80% p.a. more, how much would she have had received at maturity?
$2,700 is invested today in 4-month term deposit that has an interest rate of 2.3% p.a. At the end of the 4 months, the maturity value of the first term deposit is re-invested into a 2-month term deposit at an interest rate of 3.1% p.a. What is the maturity value at the end of the second term deposit?
In the simple interest formula I = Prt, find t when I = $28, P = $600, r = 0.03.