John is budgeting for his marriage. The venue cost $10,000. It cost $500 for each guest, and John wants 50 guests while his wife wants 60% more than that. How much would the wedding cost if John's wife gets her way?
Let's think: The bride wanted 50 * .6 = 30 more guests than the husband. So the bride wanted 50 + 30 = 80 guests. So the guests cost 80 * $500 = $40000. So the total cost was $40000 + $10,000 = $50000.. The answer is: 50000.

On the night of the dance, 400 students show up to the party. 70% of the students who showed up were invited. If 40% of those invited to the party had their invitation revoked and were not allowed into the party, how many invited students attended the party?
Let's think: On the night of the dance 70 / 100 * 400 = 280 students who showed up to the party were invited. If 40% of those invited to the party had their invitation revoked, there were 40 / 100 * 280 = 112 students who showed up and had their invitation revoked. The number of invited students who attended the party is 280 - 112 = 168.. The answer is: 168.

Carlos read 28 books in July and 30 books in August. He needed to read 100 books during his summer vacation. If Carlos read some of the books in June, calculate the number of books that Carlos read in June to meet his goal?
Let's think: Carlos read 28 books + 30 books = 58 books. He needed to read 100 books - 58 books = 42 books in June.. The answer is: 42.

Billy is counting the rings in two trees. Weather fluctuations in this area mean that each tree's rings are in groups of two fat rings and four thin rings. If Billy counts 70 ring groups in the first tree and 40 ring groups in the second tree, how much older is the first tree? (Trees grow 1 ring per year.)
Let's think:
First find the total number of rings in a ring group: 2 rings + 4 rings = 6 rings. Then subtract the number of ring groups in the second tree from the number in the first tree to find the difference: 70 groups - 40 groups = 30 groups. Then multiply that number by the number of rings in a group to find the difference in the trees' ages: 30 groups * 6 rings / group = 180 rings, or 180 years.. The answer is: 180.