Answer: The sum of $875 would be paid at the door
Step-by-step explanation: Let the number of adults be a, and the number of students be b. On day one, if 200 adults and 100 students paid a sum of $875 then we can express this as
200a +100b = 875
Then on day two, if 50 adults and 30 students paid a sum of $227.5 then we can express this too as
50a + 30b = 227.5
We now have a pair of simultaneous equations as follows;
200a + 100b = 875 ----------(1)
50a + 30b = 227.5 ----------(2)
We shall solve this by use of the elimination method. Multiply equation (1) by 30 and equation (2) by 100
6000a + 3000b = 26250 ----------(3)
5000a + 3000b = 22750 ----------(4)
Subtract equation (4) from equation (3)
1000a = 3500
Divide both sides of the equation by 1000
a = 3.5
We can now substitute for the value of a into equation (1)
200(3.5) + 100b = 875
700 + 100b = 875
Subtract 700 from both sides of the equation
100b = 175
Divide both sides of the equation by 100
b = 1.75
That means each adult paid $3.5 and each student paid $1.75. Therefore when 150 adults and 200 students attend the math fair, the money realized shall be calculated as follows;
150(3.5) +200(1.75) = x
525 + 350 = 875
The amount to be realized is therefore $875.