As a subscriber of DollarShaveClub.com, I always like to look at the little problems they put at the back of their monthly publication.1 March’s was quite spectacular, and it went as follows:
Brian received a cash gift from his parents on his birthday. He spent half of what he got, plus another $5 at the local Big and Tall store, half of what was left plus $5 on in-app Candy Crush purchases and three-fourths of what was left plus a $5 tip on all-you-can-eat wings. When he left the wings joint, he was out of cash and experiencing some wicked meat-sweats. How much did he start out with?
For your own benefit, I recommend you copy that problem, paste it into a Word document, work it out, then read the rest of this article.
There are two ways to solve this, and I’ll be interested in seeing on DSC’s blog how they choose to solve it. I’m guessing they’ll use the second method, but let’s go over them in order.
Method 1: Mathematical Approach
First, we start out by creating some variables: