I require math help

Question

 The cost of electricity is obtained as follows: A fixed charge of $a, rent of a meter $b and a charge of c cents for unit of electricity supplied Determine the total cost of using n units of electricity. 

Answer 1

You could write the problem as the following equation:

Cost = (Fixed charge "a")$ + (Rent of a meter "b")$ + c(units of electricity "n")

Writing it a bit more formally,

Cost = a$ + b$ + cn¢

If necessary, you could group "a" and "b" like so,

Cost = (a+b)$ + cn¢