Your friend bought 3 bags of wild bird seed and an $18 bird feeder. Each bag of birdseed costs the same amount. If your friend spent $45, find the cost of one bag of birdseed.

3 bags and an 18 dollar bird feeder

cost=cost of bird seed+cost of bird feeder

cost=cost of bird seed+18

cost=45

45=cost of bird seed+18

subtract 18 from both sides

27=cost of bird seed

the bird seed came in 3 bags and each bag cost the same so

27=3 times cost of 1 bag of bird seed

divide by 3

9=cost of 1 bag of bird seed

answer is $9.00