Question

Zach borrowed $4,000 from his grandfather to buy a used car so he could travel to and from work. After working for 3 years, he has saved $5,920 to pay back to his grandfather. At what interest rate did Zach borrow the money?

Answer 1

Is this simple interest I mean I am assuming it is

Answer 2

So our formula for simple interest is:
Total amount= Initial Amount+Initial Amount*Interest Rate*Years

Answer 3

Our total amount is $5920
Initial amount is $4000
Years=3
The only unknown value is Interest rate which we will subsitute with the variable x
So
5920=4000+4000*x*3
Can u solve the rest from here?