Answer: 115 Adults and 120 Children
Explanation:
We have 2 unknowns: A is the number of Adults and C is the number of children.
We'll need at least two equations to solve for two unknowns.
One equation is easy: We know that A + C = 235, the total number of people who entered the park.
The second equation comes from the second fact that was provided: total admission fees were $640. We can write the sum of the two unknowns, A and C, when multiplied by their respective admission fee:
4A + 1.5C = $640 [$4 * the number of adults plus $1.5 * the number of children]
Rearrange the first equation for either variable, A or C. I picked A:
A = 235 - C
Now use this value for A in the second equation:
4A + 1.5C = $640
4*(235-C) + 1.5C = $640
-2.5C + 940 = 640
-2.5C = -300
C = 120 children
To find A:
A = 235 - C
A = 235 - 120
A = 115 adults
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Double check to see if these value work:
C A
Fee($) 1.5 4
People 120 115
Income ($) 180 460
Total = 180 + 460 = $640
It works. 120 Adults and 115 Children.