Marcus is selling lemonade and peanuts.
Let X = lemonade
Let Y = peanuts
On Saturday, Marcus sold 5 more cups of lemonade than bags of peanuts
So, X = Y + 5 and he earned 7.05
Forming the equation.
[(Y+5)*0.75] + (Y*0.35) = 7.05
0.75Y + 3.75 + 0.35Y = 7.05
1.1Y = 7.05 - 3.75
1.1Y = 3.3
Y = 3
So the number of cups of lemonade is Y + 5 = 3 + 5 = 8
So there are 8 cups.