Answer: 20
Step-by-step explanation:
Given
The cost of an individual ticket is $25
The cost of a couple's ticket is $40
The total sale is $2500
total ticket sold is 70
Suppose there are x individuals and y couples
[tex]\therefore x+y=70\quad \ldots(i)\\\\25x+40y=2500\quad \ldots(ii)\\\text{Solving }(i)\ \text{and}\ (ii)\ \text{we get}[/tex]
[tex]x=20,y=50[/tex]
So, they sold 20 tickets of the individual.