A truck travels downhill at 90 mph (miles per hour), uphill at 72 mph, and 80 mph on flat ground. The truck takes 3 hours to travel from Fakeville to Madeupland. The return trip takes 3 and a half hours.
Find the distance, in miles, between the two towns.
2006-06-14 12:07:00 · 10 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
260 miles.
From the half-hour difference we can find the length of the hill:
t = d/v, t2-t1 = d (1/v2 - 1/v1)
d= .5/(1/72-1/90) = 180
This takes 2 hours at 90 mph, so the other hour covers 80 miles.
180+80=260
2006-06-14 12:16:52 · answer #1 · answered by injanier 7 · 4⤊ 1⤋
a*90 + b*72 + c * 80 = d
a + b + c = 3
x * 90 + y * 72 + z * 80 = d
x + y+ z = 3.5
Solve that equation and you have the answer.
Where d is the distance between the towns, a and x are downhill, b and y are uphill, and c & z are flat.
2006-06-14 19:22:02 · answer #2 · answered by Andrew T 1 · 0⤊ 0⤋
Is there really a way to tell? I mean, you don't know how many miles there are, so you don't know how much of the time he's travelling uphill, downhill, or on flat land.
2006-06-14 19:12:38 · answer #3 · answered by kellykellykelly16 3 · 0⤊ 0⤋
270
2006-06-14 19:11:57 · answer #4 · answered by Shino 2 · 0⤊ 0⤋
86 miles
2006-06-14 19:15:41 · answer #5 · answered by allie 1 · 0⤊ 0⤋
definently 260
2006-06-14 19:35:57 · answer #6 · answered by Janet A 2 · 0⤊ 0⤋
Insufficient data... need more information...
2006-06-14 19:19:24 · answer #7 · answered by Mintz 3 · 0⤊ 1⤋
Well damn that truck.
2006-06-14 19:10:23 · answer #8 · answered by Anonymous · 0⤊ 0⤋
need more info please how long does he travel up hill, downhill, & flathill?
2006-06-14 19:12:31 · answer #9 · answered by superdude 2 · 0⤊ 0⤋
No thanks, I'd just rather have 2 points.
2006-06-14 19:10:33 · answer #10 · answered by xxtra chocolate 3 · 0⤊ 0⤋