Answer:
r = 5.74%
Step-by-step explanation:
Compound interest formula is expressed as;
A = P(1+r)^t
P is the principal = $8000
A = P+I =8000 + 2000 = $10000
time t = 4years
Substitute
10000 = 8000(1+r)^4
10000/8000 = (1+r)^4
10/8 = (1+r)^4
1.25 = (1+r)^4
1.05737126344 = 1+r
r = 1.05737126344 - 1
r = 0.05737126344
r = 5.74%
This gives the rate of interest
