1. An amount of 1000 is deposited into a fund that earns interest according to the accumulation function a(t)= ek*t. The accumulated value of the account after7 years is 2316.37. Find the annual effective interest rate during the first 4 years.

2. The value of a grows according to the accumulation function a(t) = (1+0.1)² . A deposit P is made at the t=0. The fund is worth 4000 at time t=9 and worth 4500 at time t=n. Find n.