To have a maximum value, your parabola would have to open downwards. So the first 2 are wrong. Since your y-intercept is positive 4, your graph would have to touch the y axis at 4. The 3rd graph is wrong since it touches the y-axis at a negative point. The correct answer would be the 4th answer choice.
Possibly $16.89 because you multiply 55.08 and .08 to find 4.41 then you subtract that to 55.08 to find the total cost without tax which is 50.67. Then you divide by 3 because there are 3 girls to 16.89.
