Adult tickets for a play cost $18 and child tickets cost $8. If there were 21 people at a performance and the theater collected $288 from ticket sales, how many children attended the play?
Solve the system by addition. 3x + 2y = –8,
x – 4y = 16
2007-01-28 12:32:58 · 3 answers · asked by love_to_please_my_man 1 in Science & Mathematics ➔ Mathematics
1)
x+y=77
y=3x+5
x+3x+5=77
4x+5=77
4x=72
x=18
2)
18 dollars per a
8 dollars per c
a+c=21
18a+8c=288
a=21-c
18(21-c)+8c=288
378-18c+8c=288
378-10c=288
-10c=-90
c=9
3)
3x+2y=-8
x-4y=16
-3x+12y=-48
3x+2y=-8
14y=-56
y=-4
x-4y=16
x-4(-4)=16
x+16=16
x=0
x=0, y=-4
2007-01-28 12:41:10 · answer #1 · answered by Bill F 6 · 0⤊ 0⤋
Question 1 the answers are 18 and 59. 59 is 3 times 18 plus 5. 18 and 59 are 77.
Question 2. x(18) + (21-x)(8)=288
18x + 168 - 8x =288 10x +168 = 288
10x = 288-168 or x=12 # children = 21-12 = 9
Question 3 3x+2y = -8 3x+2y = -8
x -4y = 16 -3x+12y = -48
14y = -56 y = -4 x = 0
2007-01-28 20:52:52 · answer #2 · answered by LesW 1 · 0⤊ 0⤋
x+y=77
y=3x+5
x+(3x+5)=77
4x+5=77
4x=72
x=18
18+y=77
y=59
the numbers are 18 & 59
check
3*18+5=54+5=59=y
18a+8c=288
a+c=21 multiply by -8
-8a-8c=-168
18a+8c=288 add
10a=120 divide by 10
a=12
12+c=21 subtract 12
c=9
check
12*18+9*8=216+72=288
9 children (& 12 adults) attended the play.
3x + 2y = –8 multiply by 2
6x+4y=-16
x – 4y = 16 add
7x=0
x=0
2y=-8
y=-4
check
-4y=16
y=-4
(0, -4)
2007-01-28 21:29:40 · answer #3 · answered by yupchagee 7 · 0⤊ 0⤋