Q: Sammy has 8 gifts to wrap. Each gift requires 1.5 meters of ribbon. Unfortunately, she has no available ribbon so Tom let her use his 15-meter long ribbon. How many meters of ribbon will be left from Tom's ribbon?
A: The eight gifts require 1.5 meters / gift x 8 gifts = 12 meters of ribbon. So, Tom will be left with 15 meters - 12 meters = 3 meters of ribbon. The answer is 3.

Q: Cameron drives at twice the speed of his brother, Chase. But Danielle drives at three times the speed of Cameron. If it takes Danielle 30 minutes to travel from Granville to Salisbury, how long, in minutes, will it take Chase to travel from Granville to Salisbury?
A: If Danielle drives at three times the speed of Cameron, it will take Cameron 30 * 3 = 90 minutes for Cameron to travel the same distance. And since Cameron drives at twice the speed of his brother, Chase, it will take Chase 90 * 2 = 180 minutes to travel from Granville to Salisbury. The answer is 180.

Q: A math teacher had $100 to buy three different types of calculators. A basic calculator costs $8. A scientific calculator costs twice the price as the basic while a graphing calculator costs thrice the price as the scientific. How much change did she receive after buying those three different types of calculators?
A:

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
A scientific calculator costs $8 x 2 = $16. A graphing calculator costs $16 x 3 = $48. So, she spent $8 + $16 + $48 = $72 for the three calculators. Therefore, the math teacher received $100 - $72 = $28 change. The answer is 28.