
Answer: Â 115 Adults and 120 Children
Step-by-step explanation:
We have 2 unknowns: Â 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: Â 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: Â total admission fees were $640. Â We can write the sum of the two unknowns, A and C, when multiplied by their respective admission fee:
4A + 1.5C = $640 Â [$4 * the number of adults plus $1.5 * the number of children]
Rearrange the first equation for either variable, A or C. Â 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 = $640
-2.5C + 940 = 640
-2.5C = -300
C = 120 children
To find A:
A = 235 - C
A = 235 - 120
A = 115 adults
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Double check to see if these value work:
          C    A
Fee($) Â Â Â Â Â 1.5 Â Â Â 4
People     120   115
Income ($) Â 180 Â 460
Total = 180 + 460 = $640
It works. Â 120 Adults and 115 Children.