Question

Tickets to a concert cost $2 for children, $3 for teenagers and $5 for adults. When 570 people attended the concert, the total ticket receipts were $1950. Compared to the number of children in attendance, three-fourths as many teenagers attended. How many teenagers attended?
a. 200
c. 220
b. 150
d. 316

Answer 1

Answer: b 150

Step-by-step explanation:

Answer 2

Let

x--------> the number of children

y------> the number of teenagers

z------> the number of adults

we know that

$2x+3y+5z=1,950$ ------> equation A

$x+y+z=570$ -----> equation B

$y=\frac{3}{4}x$

$x=\frac{4}{3}y$ -------> equation C

Substitute equation C in equation A and equation B

$2[\frac{4}{3}y]+3y+5z=1,950$

$\frac{17}{3}y+5z=1,950$ --------> equation D

$[\frac{4}{3}y]+y+z=570$

$\frac{7}{3}y+z=570$ --------> equation E

Multiply equation E by $-5$

$-\frac{35}{3}y-5z=-2,850$ --------> equation F

Adds equation D and equation F

$\frac{17}{3}y+5z=1,950\\\\-\frac{35}{3}y-5z=-2,850\\\\---------\\\\-\frac{18}{3}y=-900\\\\y=3*900/18\\\\y=150\ teenagers$

therefore

the answer is the option

$150\ teenagers$