working out a sum please help

Question

A=5

B=0

c+2

D=10

E=2

what is the following answer ABxEE-(ED)bX(AC)e+?

how do u get the answer ,how do u work it out please advise

Answer 1

with what you have, it looks like it will be

50 x 22 - 210(0) x 52(2) + ?

so 1100 - 0 x 104 + ?

= 1100 + ?

Answer 2

A sum of money lent out at compound interest at a certain rate of interest per annum doubles itself in five years. Find in how many years the same amount of money will be eight times of itself at the same rate of interest per annum.