Can yall rate my gf for me plzz?

What is the first step of an indirect proof of a number that is divisible by two

Problem melissa is her dad build a walkway in their backyard. the walkway will be 54 feet long and 1.5 feet wide. the local hardware store sells tiles which are 1.5 by 1.5 feet and come in boxes of 12. how many boxes of tiles do they need?

Me with this one question, and i'll upvote the brainliest answer