Answer:
Adult's ticket is 7, child's ticket is 2
Step-by-step explanation:
Let adult's ticket be "x" and child's ticket be "y"
So, for family 1, the equation would be: 2x+3y=20
And, for family 2, the equation would be: 1x+4y=15
Use the substitution method in the second equation to know what x in terms of y is:
x + 4y = 15 (substact 4y from both sides)
x= 15 - 4y
Plugin y into the first equation:
2(15-4y)+3y=20 (distribute)
30-8y+3y=20 (simplify)
30-5y = 20 (get y by itself)
-5y = -10 (divide by -5)
y = 2
Now that you know the value of y (child's ticket), figure out x by plugging in 2 into any of the equations (I chose the second):
1x+4(2) = 15 (simplify)
x + 8 = 15 (subtract 8)
x = 7