Explanation:
Let's start by defining our term:
How much she had at the beginning = B
Now let's edit that value like the problem says
B - B/4 - B/8 = 40
Let's multiply everything by 8 to get rid of any denominators
8B - 2B - B = 320
5B = 320
B = 64
Answer:
Rachel had $64 at the beginning.