could you help me with the following problem?
A person takes a trip driving with a constant speed of 89.5 km/h except for a 22 min rest stop. If the person's average speed is 77.8 km/h, how long is the trip?
2006-08-23 23:22:07 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Physics
The distance covered with a speed of 89.5 km/h in a time of ‘t’ hour will be covered with a less speed of 77.8 km/h in an hour of ‘t + 22/60’ hours.
The difference between average speed and actual speed is 11.7 km/h.
The difference in distance covered during the time‘t’ is ‘11.7 x t’ and this is compensated by a distance of 77.8 x22/60 hours.
Therefore 11.7 x t = 77.8 x22/60. Or t = 2.44 hours.
2006-08-24 01:14:47 · answer #1 · answered by Pearlsawme 7 · 0⤊ 0⤋
22 min=0.36 h
distance=77.8 X time
distance=89.5 X (time - 0.36)
77.8 X t = 89.5 X t - 89.5 X 0.36
11.7 X t = 32.22
t = 2.75 hours
2 hours 45 minutes
2006-08-24 06:38:53 · answer #2 · answered by dori 2 · 0⤊ 0⤋
89.5*(t - 22/60) = 77.8*t
89.5t - 32.817 = 77.8t
11.7t = 32.817
t = 2.805 hours including rest time of 22 min
2006-08-24 06:55:18 · answer #3 · answered by nalaka 2 · 1⤊ 0⤋
1 hour...give or take 15 minutes since, depending on how far the destination is after getting off the highway and the speed limit lowers in residential areas.
2006-08-24 06:25:44 · answer #4 · answered by gnomus12 6 · 0⤊ 0⤋
I think that this how you do it:
d = 77.8 * t
d = 89.5 (t + 0.36)
solve for t = 2.75 hr.
2006-08-24 06:33:32 · answer #5 · answered by Ginny_Weasley 2 · 0⤊ 0⤋
no sorry my maths is as good as my french and they both rot
2006-08-24 06:30:07 · answer #6 · answered by Anonymous · 0⤊ 0⤋
213.95 kilometres.
2006-08-24 08:24:45 · answer #7 · answered by Sean 2 · 0⤊ 0⤋
good question
2006-08-24 06:36:21 · answer #8 · answered by maxvijay2003 3 · 0⤊ 0⤋