Ashley had a summer lemonade stand where she sold small cups of lemonade for $1.25 and large cups for $2.50. If ashley sold a total of 155 cups of lemonade for $265, how many cups of each type did she sell?

Verified Answer :

Here is the solution.
Let s = small cups and l = large cups
s + l = 155
1.25s + 2.50l = 265
s = 155 - l
(now substitute)
1.25(155-l) + 2.50l = 265
193.75 - 1.25l + 2.50l = 265
1.25l = 71.25 (divide both sides by 1.25)
l = 57
Therefore there are 57 large cups sold
Next, 
s + 57 = 155
s = 98
There are 98 small cups sold.
Hope this answers your question.

If x represent for small cups
y represent for large cups
*
\(x + y = 155 \\ y = 155 - x\)

We have the equation:
\(1.25 x + 2.50y = 265 \\ 1.25x + 2.50(155 - x) = 265\)
So
\(x = 98 \\ y = 155 - 98 = 57\)