Question 500182
Let
x=Adult Ticket
y=Children Ticket

Cost of Adult ticket = $21
Cost of Children ticket = $14

Cost of x tickets purchased=21*x
Cost of y tickets purchased=14*y

Adult tickets purchased + children’s tickets purchased = Total tickets purchased
x+y=7
x=7-y………………(1)
Cost of Adult tickets purchased + Cost of Children’s tickets purchased = Cost of total tickets purchased
21x+14y=119……..(2)
Put value of x from (1) to (2)
21(7-y)+14y=119
147-21y+14y=119
147-7y=119
-7y=119-147
-7y=-28
Divide by  -7 both sides of above equation
-7y/-7=-28/-7
y=4
Put value of y in (1)
x=7-y………………(1)
x=7-4
x=3
4 Children tickets and 3 Adult tickets were purchased.