[Question]: Bob buys nose spray. He buys 10 of them for a "buy one get one free" promotion. They each cost $3. How much does he pay?
[Answer]: He got 10 / 2 = 5 paid. That means he paid 5 * 3 = $15.
So the answer is 15.

[Question]: Alex has 2 cakes that are each cut into 8 slices. A fourth of the slices are given away to his friends. A third of the remaining slices are given away to his family. Alex eats 3 slices. How many slices of the cake are left?
[Answer]: There are 2 * 8 = 16 slices of cake. There are 16 / 4 = 4 slices. There are 16 - 4 = 12 slices left. There are 12 / 3 = 4 slices given away. There are 12 - 4 - 3 = 5 slices of cake left.
So the answer is 5.

[Question]: My new house has 12 medium ceiling lights but I have seen small and large ceiling lights in other rooms. The small ones require 1 bulb, the medium ones require 2, and the large ones need 3 bulbs. How many bulbs should I buy if my wife says she saw twice as many large ceiling lights as medium ceiling lights and ten more small lights than medium ones?
[Answer]:
If the house has twice the number of large ones as medium ones then the house has 2 * 12 = 24 large ceiling lights. Similarly, if it has 10 more small ones than the 12 medium ones then it has 10 + 12 = 22 small ceiling lights. If one small ceiling light requires 1 bulb then 22 small ones will require 1 * 22 = 22 bulbs. If one medium ceiling light requires 2 bulbs then 12 medium ones will require 2 * 12 = 24 bulbs. If one large ceiling light requires 3 bulbs then 24 medium ones will require 3 * 24 = 72 bulbs. Therefore the house will require 22 bulbs for the small ones + 24 bulbs for the medium ones + 72 bulbs for the large ones, for a total of 22 + 24 + 72 = 118.
So the answer is 118.