Answer:
325 adults and 612 students entered the school play
Explanation:
1st equation: x is the number of adults and y the number of students.
2nd equation: Students times what they payed + adults times what they payed:
1st: x + y = 937
2nd: 2x + 0.75y = 1109
x = 937 - y
Now let's replace x for (937 - y) in the 2nd equation, to find out the value of y:
2(937 - y) + 0.75y = 1109
1874 - 2y + 0.75y = 1109
1874 - 1.25y = 1109
-1.25y = 1109 - 1874
-1.25y = -765 (multiply -1)
1.25y = 765
y = 765 / 1.25
y = 612
Now that we found the y value, let's replace it in the 1st equation to find out the value of x:
x + 612 = 937
x = 937 - 612
x = 325
If you want to double check it, you can replace both in the 2nd equation, to make sure:
2 * 325 + 0.75 * 612 = 1109
650 + 459 = 1109 (checked)