Mark makes $10 for working 6 hours. if he wants to make $8 how many hours must he work?

The sum of two numbers is 86, and their difference is 20. find the two numbers

The vet charges $45 for an office visit and $10 for each vaccination your dog needs. write an eaquation

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?