Question: Bo is learning words for the GRE. He got 800 flashcards. He knew 20% of the words on them. He has 40 days to learn the rest. How many words does he need to learn a day?
Answer: He knows 800 * .2 = 160 words. So he needs to learn 800 - 160 = 640 words. That means he needs to learn 640 / 40 = 16 words per day. The answer is 16.

Question: Dani brings two and half dozen cupcakes for her 2nd-grade class. There are 27 students (including Dani), 1 teacher, and 1 teacher’s aid. If 3 students called in sick that day, how many cupcakes are left after Dani gives one to everyone in the class?
Answer: Dani brings 2.5 x 12 = 30 cupcakes. She needs this many cupcakes to feed everyone in class 27 + 2 = 29. With the 3 students calling in sick, there are this many people in class today 29 - 3 = 26. There are this many cupcakes left after everyone gets one 30 - 26 = 4 cupcakes. The answer is 4.

Question: Alison bought some storage tubs for her garage. She bought 3 large ones and 6 small ones, for $48 total. If the large tubs cost $6, how much do the small ones cost?
Answer: Let t be the price of the small tubs. 3 * 6 + 6 * t = 48. 18 + 6 * t = 48. 6 * t = 48 - 18 = 30. 6t = 30. t = 5 dollars for each small tub. The answer is 5.

Question: For the funfair, the school organizers ordered 30 rolls of tickets. Each roll of tickets has 100 tickets. The 4th graders bought 30% of the tickets while the 5th graders bought 50% of the remaining tickets. Then the 6th graders bought a total of 100 tickets. How many tickets were left unsold?
Answer:
There were a total of 30 x 100 = 3000 tickets ordered by the school organizers. The 4th graders bought 3000 x 30 / 100 = 900 tickets. So, there were 3000 - 900 = 2100 tickets left for the other two grade levels. The 5th graders bought 2100 x 50 / 100 = 1050 tickets. So, 2100 - 1050 = 1050 tickets were left then. Since 100 tickets were bought by the 6th graders, therefore 1050 - 100 = 950 tickets were left unsold. The answer is 950.