PLS, I need help I don't understand this!!:(

If 1 km = 0.621 miles, how many miles are in a centimeter

In a school 2/3 of the students study a language of those who study a language 2/5 study french

Abiologist is recording the loss of fish in a pond. he notes the number of fish, f, in the pond on june 1. on july 1 there were 63 fish in the pond, which is 52 fewer fish than were in the pond on june 1. which equation represents this situation? a. f – 52 = 63 b. f – 63 = 52 c. 63 – f = 52 d. f – 63 = –52