Question 985760

I am not certain what type of problem this is my daughter has so I hope I have selected the appropriate topic.  My email address has been entered for the answer as well.

You are selling candy bars and sell 1/5 of them on the first day.  You have 40 left.  How many did you start with?  

 40 x 1/5
(multiply 5/5x 40 in order to get the common denominator) = 200/5 + 1/5 = 201/5
201/4 = 401/5

I hope that makes sense.  Thanks
<pre>If you sold {{{1/5}}}, then you're left with {{{4/5}}} of what you began with
Now you can ask: "{{{4/5}}} of what number gives me 40?"
Translated into mathematical terminology, and with N being number you began with, this becomes:
{{{4/5}}} of N = 40
{{{(4/5) * N = 40}}}
{{{4N/5 = 40}}}
4N = 200 ------------ Cross-multiplying
N, or number you started with = {{{200/4}}}, or {{{highlight_green(50)}}}