Respuesta :
The cost of one ticket will be £8.20
Explanation
Suppose, the cost of one ticket is [tex]x[/tex]
As the offer says "buy 3 tickets and get a ticket free" , it means they actually need to pay for 3 tickets.
So, the total cost of 3 tickets [tex]=3x[/tex]
Each of four friends pay £6.15 , so the total amount they pay [tex]=\£6.15 *4 = \£24.60[/tex]
Thus, the equation will be .....
[tex]3x=24.60\\ \\ x=\frac{24.60}{3}=8.20[/tex]
So, the cost of one ticket will be £8.20