You use about 15 gallons of water when you shower. if you take 20% less time when you shower, estimate how many gallons of water you would use in a week if you took a shower a day.
a. 100
b. 85
c. 40
d. 20

Astudent draws two parabolas on graph paper. both parabolas cross the x-axis at (–4, 0) and (6, 0). the y-intercept of the first parabola is (0, –12). the y-intercept of the second parabola is (0, –24). what is the positive difference between the a values for the two functions that describe the parabolas? write your answer as a decimal rounded to the nearest tenth