Question

Please help. Sally travels by car from one city to another. She drives for 20.0 min at 83.0 km/h, 41.0 min at 44.0 km/h, and 42.0 min at 50.0 km/h, and she spends 5.0 min eating lunch and buying gas.A) Determine the average speed for the trip.B) Determine the total distance traveled.

Answer 1

Given:

• She drives for 20.0 min at 83.0 km/h

,

• Also, she drives for 41.0 min at 44.0 km/h

,

• 42.0 min at 50.0 km/h

,

• She spends 5.0 minutes eating and buying gas.

Let's find the following:

(a) Determine the average speed for the trip.

To find the average speed, apply the formula:

`\text{speed}=\frac{\text{total distance}}{time\text{ travelled}}`

To find the total distance, we have:

`\begin{gathered} \text{distance}=\text{speed}\ast time \\ \\ \text{distance}=((20)/(60)\ast83)+((41)/(60)\ast44)+((42)/(60)\ast50) \\ \\ Total\text{ distance=(}0.33\ast83)+(0.683\ast44)+(0.7\ast50) \\ \\ \text{Total distance = }27.67+30.07+35 \\ \\ \text{Total distance=}92.74\text{ km} \end{gathered}`

The total distance travelled is 92.74 km

• Total time travelled:

`\begin{gathered} Time=20+41+42+5=108\text{ mins} \\ \\ \text{Convert to hour:}(108)/(60)=1.8\text{ hours} \end{gathered}`

Therefore, to find the average speed, we have:

`\text{Avg. sp}eed=\frac{Total\text{ distance}}{Time}=(92.74)/(1.8)=51.52\text{ km/h}`

Therefore, the average speed for the trip is 51.52 km/h

(b) Total distance travelled.

From part A, the total distance travelled has already been calculated.

Total distance = 92.74 kilometers.