Answer:


Step-by-step explanation:
Let x be the number of adult tickets and y be the number of children's tickets.
We are given that there are total 12 people. Therefore, we can set:

Moreover, we are given that an adult ticket costs $21.50 and a child's ticket costs $14.75, therefore, cost of x adult tickets will be
and cost of y children's ticket will be
. We can form the second equation by setting the total cost of tickets as:

Therefore, the required system of equations that could be used to find x and y will be:


Answer:
<u>Number of students:</u>
<u>Total of marks:</u>
- 5*6 + 4*7 + 7*8 + 10*9 + 4*10 = 244
<u>Mean mark:</u>
Try dividing the two numbers maybe I really don’t know