Question

Donna sells boxes of cookies for $4 each. Pablo sells boxes of cookies for $6 each. Each of them sold the same dollar amount. It was the smallest dollar amount for which this was possible. What is the dollar amount each of them sold?

I need to find the lcm right?

Answer 1

You are absolutely right - you need the Lowest Common Multiple (LCM). It's $12.

Explanation:

There are different ways to find an LCM - here are a couple:

List out multiples and find commonalities:

`4, 8, color(red)(12), 16, ...`
`6, color(red)12, 18, ...`

For bigger LCM's, I really like doing a prime factorization:

`4=2xx2`
`6=2xx3`

The LCM will take the largest grouping of each prime. There is a group of two 2's in the 4, so we take those, and there's a single 3 in the 6, so we take that:

`LCM=2xx2xx3=12`