when janette was 5 years old, her grandmother deposited $2500 into a savings account for her. the account pays a simple annual interest rate of 4%. what will the balance be when janette turns 15 years old?

a. $40
b. $1000
c. $2540
d. $3500

The expected value (or expected profit in this case) is X = ∑xₙpₙ, where xₙ is the "outcome" ( in this case, winning or losing money) and pₙ is the probability of such outcome.

then, If you have a 0.7 chance of winning $23000, and a 0.3 chance of losing $12.000, the expected value is : 0.7*$23000 - 0.3*$12000 = $12500.

So the expected profit is $12500.