Question

WILL MEDAL AND FAN!!!
John and Mike are carpooling to see their favorite baseball team play. On their way to the game, they drove 60 miles in the first 45 minutes of the trip. Unfortunately then they ran into heavy traffic and were only able to travel at a constant speed of 20 miles per hour. Choose the correct function which describes the average speed during the entire trip as a function of time, h, in hours.

Question 6 options:

f(h)=60+20(h−0.75)h where h≥0.75

f(h)=20h+1.3

f(h)=60h+20

f(h)=60h+45h

Answer 1

@SolomonZelman could you help? ill medal.:)

Answer 2

@superdavesuper

Answer 3

Were you able to figure out how far they traveled at any given time h ?

Answer 4

well at least 45, i was thinking its option D?

Answer 5

so they travel 60 mi in the first part of their trip

how far do they travel on the second part?

Answer 6

20mph

Answer 7

other than that we dont know

Answer 8

that's the speed for the second part

Answer 9

let's say they travel 20 mph for h hrs

the distance would be 20*h, no?

Answer 10

yes

Answer 11

so b?

Answer 12

here's the thing though: they didn't travel a full h hours for 20 mph

they spent the first 0.75 hrs going some speed (first part of the trip)
then the rest of the h-0.75 hrs is them going 20 mph

Answer 13

so they travel 60 mi on the first leg of the trip

then an additional 20(h-0.75) for the second leg

Answer 14

in total, they travel a distance of `60 + 20(h - 0.75)` miles

Answer 15

to find the average speed over the entire trip, you divide that total distance by the total time (in this case, h)

so the average speed is \(\Large \frac{60 + 20(h - 0.75)}{h}\) mph

Answer 16

ohh huh i wouldnt have guessed that...

Answer 17

thank you:)

Answer 18

yeah it's probably not the most intuitive thing out there, but just remember


distance = rate*time

rate = distance/time


"rate" is another term for "speed"