Problem 2-62 - Distance and speed - Part 3 (c)

A truck travels at \(80 \;km/h\) for \(30 \;min\), then at \(60 \;km/h\) for \(1.5 \;hr.\) Assuming 2 significant digits in the given numbers, calculate the truck's
(a) total distance traveled, and
(b) average speed.

Accumulated Solution

\(\mathrm{speed = \frac{d}{\Delta t }\\ d = (speed) \Delta t}\)

Correct!
\(\mathrm{d = (speed) \Delta t}\)

How far does the truck travel at the first speed?

(A)  \(\mathrm{80 \times 30 = 2400\; km}\)

(B)  \(\mathrm{80/30 = 8/3 \;km}\)

(C)  \(\mathrm{80(1/2) = 40\; km}\)