the cost of a field trip is $220 plus $7 per student. if the school can spend at most $500, how many students can go on the field trip?

Subtract 220 from 500 to get the amount that you have for students.

you should have 280 left

then divide that by 7

here's a easy way to do this. If you know that 28/7 is 4, then 280/7 will be the same as 4•10 since 28•10 is 280

4•10=40, which means 40 students can go on this trip.