Question 19986
Let x be the adults tickets
Let y be the childern tickets

x+y=7
y=7-x
5(x)+3(y)=27 (substitute)
5x+3(7-x)=27
5x+21-3x=27
2x+21-21=27-21
2x=6
{{{2x/2=6/2}}}
x=3
7-3=4
Therefore there were 3 adults ticket purchased and 4 childer tickets purchased.