Question 193776
the annual interest rate = r 
$8,000 in a savings account for two years.--> 8000*(1+r)^2
beginning of the second year, an additional $2,500 is invested-->2500*(100+r)
8000*(1+r)^2 + 2500*(1+r) = 11,445
let 100+r = A
:

8000*A^2 + 2500*A = 11,445:

8000*A^2 + 2500*A - 11,445 = 0:

A = 1.05
:
r = 0.05 or 5 % Ans.