Let ‘x’ be the price of adult ticket.

Let ‘y’ be the price of student ticket.

On the first day, 6 adult tickets and 16 student tickets were sold and the total ticket sales was $312.

that is: 6x+16y=312 ————equation 1

On the Second day, 7 adult tickets and 7 student tickets were sold and the total ticket sales was $189.

that is: 7x+7y=189 ————equation 2

that is: 7x+7y=189 ————equation 2

Solving equations 1 and 2,

Multiplying 1st equation with 7 on both sides:

7(6x+16y=312)

42x+112y=2184 ———equation 3

Multiplying 2nd equat with 6 on both sides:

6(7x+7y=189)

42x+42y=1134. ———-equation 4

Multiplying equation 4 with ‘-‘ (minus) on both sides:

-42x-42y=-1134

solving equation 3 and 4:

42x+112y=2184

-42x-42y=-1134

—————————-

70y=1050

y=1050/70

y=15

therefore, price of student ticket ‘y’ is $15.

now substitute this y value in any of the equations above to get x value.

lets take equation 2:

7x+7y=189

7x+7*15=189

7x+105=189

7x=189-105

7x=84

x=84/7=12

therefore, price of adult ticket ‘x’ is 12.