Answer: 120
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Explanation:
n = number of people invited
n+2 = total number of people after adding Oscar and Julie
36(n+2) = total cost before the $90 fee
36(n+2)+90 = total cost after the $90 fee
Set that equal to the budget of 4500 and isolate n
36(n+2)+90 = 4500
36n+72+90 = 4500
36n+162 = 4500
36n = 4500-162
36n = 4338
n = 120.5
n = 120
We round down so that we don't go over budget
Oscar and Julie can invite 120 people.
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Check:
If n = 120 then 36(n+2)+90 = 36(120+2)+90 = 4482 which is under budget
If n = 121 then 36(n+2)+90 = 36(121+2)+90 = 4518 which is over budget
This confirms that 120 is the answer.
