Question

The Chang family is on their way home from a cross-country road trip. During the trip, the function D (t) = 3260 - 55t can be used to model

their distance, in miles, from home after t hours of driving.
part a:find D(12) and interpret the meaning in the context of the problem. part b: if D(t) =2490, find the value of t and interpret its meaning in the context of the problem

Answer 1

See below.

Explanation:

D(t) = 3260 - 55t

The function that shows their distance from home as a function of time shows that they started 3260 miles from home and are driving at 55 miles per hour.

part a:

D(12) = 3260 55(12)

D(12) = 3260 - 660

D(12) = 2600

Interpretation: After 12 hours of driving home, they are 2600 miles from home.

part b:

D(t) = 2490

3260 - 55t = 2490

-55t = -770

t = 14

Interpretation: When they are 2490 miles from home, they have driven for 14 hours.