[Question]: John has to replace the ball bearings for machines he works with. He has 10 machines and they take 30 ball bearings each. It normally costs $1 per ball bearing but right now there is a sale where they are only $.75. Also since he is buying in bulk he gets a further 20% discount. How much money did he save by buying them all during the sale rather than 1 at a time?
[Answer]: He needs to replace 30 * 10 = 300 ball bearings. The normal price is 300 * 1 = $300. Because of the sale he only has to pay 300 * .75 = $225. He then gets a discount which shaves another 225 * .2 = $45 off the price. That means he only pays 225 - 45 = $180. So he saved 300 - 180 = $120.
So the answer is 120.

[Question]: A local college is offering German lessons and currently has 8 students enrolled. Through advertising, 8 more became interested but a fourth of these dropped out within a day. 2 more got frustrated and left. The class then rallied to show how simple the course actually is and increased enrollment by 5 times the amount of students already enrolled in the class, but 2 had to drop it because of scheduling conflicts. After one last rally, 6 more people enrolled. As the days passed, half of the class eventually dropped, and half of the remaining students graduated. How many are still enrolled?
[Answer]: 8 + 8 = 16 students are enrolled in the German class. 8 * .25 = 2 dropped out from the new recruits. 2 more left, so the class had 16 - 2 - 2 = 12 students left. There were 12 * 5 + 12 = 72 total students in the class after the rally. Two people had to drop the class, so there were 72 - 2 = 70 left. 70 + 6 = 76 were enrolled after the final rally. 76 / 2 = 38 are left after half the class dropped. 38 / 2 = 19 are left after half the class graduated.
So the answer is 19.

[Question]: Adam has 18 magnets. He gave away a third of the magnets, and he still had half as many magnets as Peter. How many magnets does Peter have?
[Answer]:
Adam gave away 18 / 3 = 6 magnets. Adam had 18 - 6 = 12 magnets left. Peter has 12 * 2 = 24 magnets.
So the answer is 24.