Chelsea invested $15,000 at 4% interest compounded annually. How much interest will she earn in 4 years?

P = 15000, r = 4% = 0.04 per year, n = 4 years.

A = P (1 + r) ⁿ

A = 15000 (1 + 0.04) ⁴

A ≈ 15000 (1.04) ⁴ ≈ 17547.88

Interest = Amount - Principal = 17547.88 - 15000 = 2547.88

Interest ≈ $ 2547.88

The future worth (F) of the money invested now (P) with the compounded interest (i) is calculated by the equation,

F = P x (1 + i) ^n

where n is the number of years. Substituting the known values,

F = ($15,000) x (1 + 0.04) ^4

The value of F is $17,547.88.