Answer:
612 adults
361 students
Step-by-step explanation:
To solve this question, set two equations:
Let x be number of adults and y be number of students.
As there are in total 937 people, the equation would be the sum of both adults and children:

...... ( 1 )
As the total sale amount is $1109, the equation would be to add up the ticket fee:
...... ( 2 )
Put ( 1 ) into ( 2 ):





Put y into ( 1 ):


Therefore there are 612 adults and 361 students.
The answer is $412.
Let's first calculate simple interest. Simple interest (I) can be expressed as:
I = P * r * t
P - principal
r - rate
t - time period
It is given:
I = ?
P = $400
r = 3% = 0.03
t = 1 year
Therefore:
I = P * r * t = 400 * 0.03 * 1 = 12
The total amount Kate will repay is the principal amount (P) plus 3% simple interest (I):
P + I = 400 + 12 = $412
A=number of seats in section A
B=number of seats in section B
C=number of seats in section C
We can suggest this system of equations:
A+B+C=55,000
A=B+C ⇒A-B-C=0
28A+16B+12C=1,158,000
We solve this system of equations by Gauss Method.
1 1 1 55,000
1 -1 -1 0
28 16 12 1,158,000
1 1 1 55,000
0 -2 -2 -55,000 (R₂-R₁)
0 12 16 382,000 (28R₁-R₂)
1 1 1 55,000
0 -2 -2 -55,000
0 0 4 52,000 (6R₂+R₃)
Therefore:
4C=52,000
C=52,000/4
C=13,000
-2B-2(13,000)=-55,000
-2B-26,000=-55,000
-2B=-55,000+26,000
-2B=-29,000
B=-29,000 / -2
B=14,500.
A + 14,500+13,000=55,000
A+27,500=55,000
A=55,000-27,500
A=27,500.
Answer: there are 27,500 seats in section A, 14,500 seats in section B and 13,000 seats in section C.
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