Can some one explain how to get the answer to this : the record for the most amount of rain in the shortest periodontal time in the us was 12in. in 42 minutes. how much rain fell in 15 minutes? and in 28 minutes?

Do 42 divided by 15 then divided 12 by the awnser. And you do 42 divided by 28 and divided that by 12 I think I'm pretty sure

Shantel donates 15% of the 40 books to the national library.
40(.15) = 6
She also sells 3/5 of the 40 books or 60% of it.
3/5 = x/40
Cross multiply
3(40) = 5x
120 = 5x
Divide both sides by 5
x = 24

24 + 6 = 30
Subtract the number of books she sold or donated
40 - 30 = 10

Shantel has 10 books left in her book collection.