The answers are B and C.
If Paula earns $12 per driveway, then she earns 12 * 6 dollars on Saturday and 12 * x dollars on Sunday.
Turn the word problem into an equation:
(12 * 6) + (12 * x) = 144
Factor out the $12:
12(6 + x) = 144
This equation is identical to the third answer, so one answer is C.
Now solve for x, the number of driveways:
12(6 + x) = 144
[12(6 + x)]\12 = 144\12
6 + x = 12
6 + x - 6 = 12 - 6
x = 6.
Since the number of driveways is 6, the second answer is B.
