Answer:
3.5%
Step-by-step explanation:
First you need to know the simple interest and the amount formulas. This is as expressed as;
Interest I = PRT/100 ... 1
Amount A = P+I ...2
From 2;
I = A - P ....3
Substitute 3 into 1
A - P = PRT/100
Given the following
Amount A = $27,780
Principal P = $24000
Time T = 54/12 yrs
Required
Rate R
Substitute
$27,780 - $24000 = 24000 * R * 54/1200
3,780 = 20 * 54R
3780 = 1080R
R = 3780/1080
R = 3.5%
Hence the interest rate is 3.5%
