Angela invest $2550 at 3% interest rate compounded annually. what will the balance in the account be after 1.5 years?

The formula for compound interest is as follows:
 A = P (1 + r/n)^(nt)

A is the total money, P is the initial amount, r is the annual interest rate, n is the number of times a year the interest is compounded, and t is the years for which the money is invested.

Let's plug in your numbers.

A = 2550 + (1 + 1.03/1)^(1*1.5)

Simplify what's in the parentheses. 

A = (2550) + (2.03)^(1.5)

Now take 2.03 to the power of 1.5.

A = (2550) + 2.89230479

Add.

A = 2552.8923

Which comes to roughly $2552.89.