How to similarity and proportions

Cassie is traveling 675 miles today to visit her brother and his family. so far, she has stopped for gas three times. at the first stop, she put in 7.1 gallons of gas and paid $23.79. at her second stop, she put in 5.8 gallons of gas and paid $19.08. and, at the third stop, 6.6 gallons and paid $20.39. at which stop did casey pay the most for gas?

Collin did the work to see if 10 is a solution to the equation r/4=2.4

Olivia is using 160 quilt squares to make a red, yellow, and blue quilt if 25% of the quilt are red and 30% are yellow how many quilt squares are blue