The format is y = mx + b
where y would be your C
x would be your M
m would be the price per mile (2.20)
and b would be your initial fee (2.75)
put this together in that format and we get
C = 2.20M + 2.75
42.87*0.15= $6.43 rounded
The answer is 6⁴.
Exponent is the number of times the factor is being multiplied. For example:
x * x = x²
x * x * x = x³
x * x * x * x = x⁴
....
So:
6 * 6 * 6 *6 = 6⁴