Question

The equation yˆ=−5.131x2+31.821x−3.333 approximates the number of people standing in line to catch a commuter train x hours after 5 a.m. What is the best estimate for the number of people in line at 8 a.m.?

a.32
b.40
c.46
d.77

Answer 1

Given that y is the number of people in the line after 5 am and there are already 3 hours that have passed for 8 am, we substitute 3 to the equation to find the answer.
y = (-5.131)(3²) + 31.821(3) - 3.333
Simplifying,
y = 45.951
Thus, the answer is letter C. 46.