Question

HELP


Frank drove to the mountains last weekend. There was heavy traffic on the way there, and the trip took
8
hours. When Frank drove home, there was no traffic and the trip only took
5
hours. If his average rate was
21
miles per hour faster on the trip home, how far away does Frank live from the mountains?
Do not do any rounding.

Answer 1

Probably easiest to solve for his speed first and then the distance.

Answer 2

d=r*t and same distance so first rate times time equals the second rate times time.

Answer 3

@EVOKER sorry i was gone

Answer 4

can you help @wolf1728

Answer 5

Yes I think I can

Answer 6

Average rate was 21 miles per hour
Total time = 8 + 5 = 13 hours
distance = rate * time
d = 21 mph * 13 = 273 (which is twice the distance)
so distance = 136.5 miles

Trip to the mountains is 8 hours and distance = 136.5 miles so rate = 17.0625 mph
Trip back - 5 hours; 136.5 miles = 27.3 mph

Average speed = 17.0625 * 8 + 27.3 * 5 = 273/13 hours = 21 mph

Answer 7

so it's 136.5

Answer 8

yes 136.5 miles

Answer 9

it was wrong

Answer 10

it said it is wrong?

Answer 11

yeah

Answer 12

Oh, it says the average rate was 21 miles per hour FASTER on the way home.
(I thought the average rate was 21 miles per hour - my mistake) Guess I'll recalculate

Answer 13

distance = rate * time
let's say distance = x
rate on the way up = x/8
rate on way back = x/5
x/5 = x/8 + 21
21 = x/5 -x/8
21 = 8x/40 -5x/40
21 = 3x/40
840 = 3x
x = 280 miles

Answer 14

IT WAS RIGHT.

Answer 15

Thank you

Answer 16

you are welcome - and I'm glad I could redeem myself :-)

Answer 17

Can you do one more?

Answer 18

Okay - go ahead

Answer 19

Two trains leave the station at the same time, one heading east and the other west. The eastbound train travels
10
miles per hour slower than the westbound train. If the two trains are
450
miles apart after
3
hours, what is the rate of the eastbound train?
Do not do any rounding.

Answer 20

distance = rate * time
450/3 hours = 150 miles per hour (COMBINED rate)
one train is 10 mph faster so rate = 80 mph and slower = 70 mph

Check: 80* 3 = 240 miles and 70*3 = 210 miles
240+210= 450 miles So that checks out

80 mph and 70 mph

Answer 21

70 mph eastbound train

Answer 22

Right again

Answer 23

Thank you for the help

Answer 24

Okay - I'm glad I was right on my first try!! LOL
u r welcome

Answer 25

Lol