Michael drove 210 miles using 9 gallons of gas. at this rate, how many gallons of gas would he need to drive 413 miles?

Jiovanni is looking in to two different companies that offer study guides for math exams.test prep 101 charges a $5 flat fee and an additional $0.25 per problem.math charges a $2 flat fee and an additional $0.50 per problem.how many prablems would make the costs of the two companies be equal? varibles: equations/eniqualities{ {