Compounding Interest-Find Time or Principal

Question

How long will it take for $2800 to grow to $3000 if invested at 4% interest compounded semiannually?

Answer 1

3000 = 2800(1+.04/2)^2t solve for t

15/14 = 1.02^2t

1.02^2t = about 1.07

2t = about 3.484

t = about 1.742 years

in 1 year 2800 become 2800(1.02)^2 = 72628/25=2,913.12

in 2 years 2800 becomes 2913.12(1.02)^2 = 3030.81

it reaches $3000 a little before 2 years