Solution

Amount = 1500(1.2)^3 = 1.5*1728 = 2592 (if entire amount is paid at the end of 3 years)

now if x is paid in first year, then future value (at the end of 3 years) of x  = x(1.2)^2 = 1.44 x

same x paid in second year, then future value (at the end of 3 years) of this x  = x (1.2) = 1.2 x

and at the end of third year another x is paid

in total value of installments at the end of 3 years 

1.44x+1.2x+x = 3.64x = 2592

x = 712