The coffee shop has green mugs and blue mugs. There are 6 less than three times as many blue coffee mugs as green coffee mugs. There are 42 blue coffee mugs. How many green
coffee mugs are there?

There are 16 green coffee mugs.

You have to work backwards in order to get your answer.

“6 less than” backwards means you should add 6.
6 + 42 = 48

“Three times as many” backwards means you divide by 3.
48/3 = 16

You can check your work by plugging it back into the original question.

16 green coffee mugs * 3 - 6 = 42 blue coffee mugs