Money accumulates in a fund at an effective annual interest rate of i during the first 4 years, and at an effective annual interest rate of 2i thereafter. A deposite of 1 is made into the fund at time 0. It accumulates to 2.50 at the end of 10 years and to 10.22 at the end of 20 years. What is the value of the deposit at the end of 7 years