Question

Sally travels by car from one city to another. She drives for 22.0 min at 52.0 km/h, 46.0 min at 42.0 km/h, and 47.0 min at 27.0 km/h, and she spends 5.0 min eating lunch and buying gas.
(a) Determine the average speed for the trip.km\h



(b) Determine the total distance traveled. km

Answer 1

shane thanks for the help on the last one i figured that one out

Answer 2

If you want I can check your answers once you've calculated these

Answer 3

sure

Answer 4

for average i got 1.008 for total distants i got 121.0

Answer 5

\[52.0+42.0+27.0=121.0\]

Answer 6

\[22.0+46.0+47.0=115+5=120\]

Answer 7

I must be tired...I goofed up a symbol in my initial post. Here it is again:
\[speed=\frac{distance}{time}\]a) To calculate the average speed you take the total distance traveled and divide that by the total time it took to cover that distance.

b) The total distance traveled will be the sum of the distances for each leg of her trip.

Having said that, please redo the calcs.

Answer 8

Since speed = distance/time, distance = speed x time. That's how you calculate the distance for each leg.

Answer 9

i added the distances together and i added the time together so all i have to do is \[121.0\120 \right?\]

Answer 10

No. I'll show you how to calculate the distance of the first leg:

22min @ 52 km/hr
Therefore the distance for that leg will be:\[(\frac{22}{60}h)*52km/h=19.067km\]

Answer 11

oh ok

Answer 12

u forgot to say i have to turn the min into hours

Answer 13

You always have to convert units if they are different :)

Answer 14

thats the step i was mising

Answer 15

now i calculated all 3 legs now what

Answer 16

What distances did you get for each leg? You just need to sum them up to get a total and then divide that by the total time of 120 mins (2 hrs).

Answer 17

19.07,32.2,21.15 there right webassign confirmed it now for the average speed

Answer 18

72.42 total distance

Answer 19

Right....so the average speed would be:\[Speed_{avg}=\frac{72.42km}{2hr}=?\]

Answer 20

why 2 hours?

Answer 21

120 minutes = 2 hours. The original speeds were given in km/h so I would put the answer in km/h.

Answer 22

u included that extra 5 minutes at the end?

Answer 23

Yes...remember you added them up (and I checked):
22.0+46.0+47.0+5.0=120

Answer 24

then is it 36.21?

Answer 25

Yep

Answer 26

nice! got a 76 on the webassign so far ur a great teacher

Answer 27

I probably could have explained it better but you got it :)

Answer 28

can i ask the next question in here

Answer 29

No guarantees but maybe I can help with it

Answer 30

okay

Answer 31

You should post it as a separate question just in case...so everyone else can see it

Answer 32

ok