Question: A library has a number of books. 35% of them are intended for children and 104 of them are for adults. How many books are in the library?
Answer: 65% of the library books are for adults because 100 - 35 = 65. There are 160 library books in total because 104 / .65 = 160. The answer is 160.

Question: A dog barks 30 times per minute. If 2 dogs bark 30 times per minute, how many times will they have barked after 10 minutes?
Answer: There are 2 dogs and they each bark 30 times per minute so together they bark 2 * 30 = 60 times per minute. 2 dogs bark a combined total of 60 times per minutes, after 10 minutes they will have barked 60 * 10 = 600 times. The answer is 600.

Question: Jake has $5000. He spends $2800 on a new motorcycle, and then spends half of what's left on a concert ticket. Jake then loses a fourth of what he has left. How much money does he have left?
Answer: Jake has 5000 - 2800 = $2200 left. Jake has 2200 / 2 = $1100. Jake loses 1100 / 4 = $275. Jake has 1100 - 275 = $825 left. The answer is 825.

Question: There were some snowflakes at first. It snowed an additional 4 snowflakes every 5 minutes. If there were 58 snowflakes after 1 hour, how many snowflakes were there at first?
Answer:
There are 60 / 5 = 12 5 - minute intervals in 1 hour. 12 * 4 = 48 snowflakes fell in 1 hour. There were 58 - 48 = 10 snowflakes at first. The answer is 10.