A man takes 2 hours and 43 minutes less to ride with the wind from towm A to town B than from B to A against the wind. He rides at an average speed of 49/4 km/h when going with the wind and at 7.35 km/h when going against it. Find the exact distance, in km, from A to B.
2007-02-10 19:32:55 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Ans is 49.19875 km
Explanation:
Let distance be x.
Time taken against wind = x/7.35
Time with the wind = 4x/49
x/7.35 - 4x/49 = 163/60
Solving for x we get,
x = 49.91875 km
2007-02-10 19:46:15 · answer #1 · answered by Nimish A 3 · 0⤊ 0⤋
Downwind time = t mins
Upwind time = t + 163 mins
D = st = (49/4) t
Also D = 7.35 t = 7.35(t + 163)
Therefore:-
(49/4) t = 7.35 ( t + 163)
49 t = 29.4( t + 163)
49 t - 29.4 t = 4792.2
19.6 t = 4792.2
t = 4792.2 / 19.6 mins = 4.07 hours
D = 49/4 x 4.07 km
D = 49.9 km is distance from A to B
2007-02-11 07:38:14 · answer #2 · answered by Como 7 · 0⤊ 0⤋
The answer is 49.91875km
Let the time taken to ride from A to B = x
Then the time from B to A = x - (2h43m) = x - 2.7167
Distance between A & B = 7.35x or 12.25*(x-2.7167)
Thus, we get the equation..
7.35x = 12.25*(x-2.7167), which is simplified to..
7.35x = 12.25x - 33.27167
And thus, x = 6.791667
Therefore the distance between A & B = 7.35 * 6.791667
= 49.91875km
2007-02-11 04:39:26 · answer #3 · answered by mustibabu 1 · 0⤊ 0⤋