Answer:
1100 adults and 1400 students
Step-by-step explanation:
Let S = students and A = adults.
We have two conditions.
(1) 5S + 10A = 18 000
(2) S + A = 2500 Subtract A from each side
(3) S = 2500 – A Substitute (3) into (1)
5(2500 – A) + 10A = 18 000 Remove parentheses
12 500 – 5A + 10 A = 18 000 Combine like terms
12 500 + 5A = 18 000 Subtract 12 500 from each side
5A = 5500 Divide each side by 6
(4) A = 1100 Substitute (4) into (2)
S + 1100 = 2500 Subtract 1100 from each side
S = 1400
There were 1100 adults and 1400 students.
<em>Check:
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5 × 1400 + 10 × 1100 = 18 000 1400 + 1100 = 2500
7 000 + 11 000 = 18 000 2500 = 2500
1 8 000 = 18 000