Yoon buys a box of markers for $2.85 but he has a coupon for 20% off how much does he save with the coupon

Which expression is equivalent to? assume x > 0 and y > 0.

Two airplanes start at the same place and travel in opposite directions,one at 395 miles per hour and the other at 422 miles per hour. how many hours will it take for the planes to be 2451 miles apart?

Aschool had an election where the candidates received votes in the ratio 1: 2: 3. if the winning candidate received 210 votes, how many total people voted in the election?