Please explian how to figure out the the initial interest rate of the ARM ?

Given th these facts thanks :)

Ben bought a home with an adjustable-rate mortgage. The margin on the loan is 2.7% and the rate cap is 7.2% The current index rate is 4.3%

2 answers

beck put $3000 in a saving account. At the end of 5 years, the account had earned $900 in interest . At what annual simple interest rate did the account grow.
Calculate i,interest rate