1) a. x = number of cars
b. x - 12
2) a. x = number of packages
b. 16 + 1/2x
3) a. x = number of coins
b. 1/2x - 6
4) 17 + x = 78
Subtract 17 from each side.
x = 61
5) x - 33 = 78
Add 33 to each side.
x = 111
6) x * 84 = 327.6
Divide each side by 84
x = 3.9
7) 1333/8.6 = 155
The speed was 155mph.
8) 2475/110 = 22.5
The trip took 22 and a half hours. (Or "The trip took 22.5 hours."