Question

The equation yˆ=−5.131x 2+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 7 a.m.?

23
27
32
40

Answer 1

40

Explanation:

The other three numbers are low.

Answer 2

For this case we have the following equation:

`y = -5.131x ^ 2 + 31.821x - 3.333`
When it's 5 a.m. then x = 0
Therefore, when it is 7 a.m. then x = 2.
Substituting x = 2 in the equation we have:

`y = -5.131 * (2) ^ 2 + 31.821 * (2) - 3.333 y = 39,785`
Rounding to the nearest whole number:

`y = 40`
Answer:
the best estimate for the number of people in line at 7 a.m. is:
y = 40