I ve been trying to figure this question for 30 min, still don t get it.?
2018-09-25 3:12 am
A jet traveled with the wind for 2 hours and returned in 2 hours and 10 min. If the total trip is 2080 km, find the speeds of the jet and the wind.
回答 (9)
2018-09-25 3:48 am
Each trip is 1040 so you let J be the jet speed and w the wind speed and then using speed x distance = time
1. (J + W) * 2 hours = 1040
2. (J - W) * 2.167 hours = 1040 **10 minutes = 0.167 hours**
1. simplifies to J + W = 520
2. simplifies to J - W = 480
Add 1 and 2
2J = 1000
J = 500 km/h
W = 20 km/h
1. (J + W) * 2 hours = 1040
2. (J - W) * 2.167 hours = 1040 **10 minutes = 0.167 hours**
1. simplifies to J + W = 520
2. simplifies to J - W = 480
Add 1 and 2
2J = 1000
J = 500 km/h
W = 20 km/h
2018-10-01 4:45 am
J+W=520
J-W=1040 x (6/13)=480, not 480-1=479.
J=500;W=520-500=20
Jet speed is 500 km/hr.and wind speed is 20 km/hr.
J-W=1040 x (6/13)=480, not 480-1=479.
J=500;W=520-500=20
Jet speed is 500 km/hr.and wind speed is 20 km/hr.
2018-09-26 5:16 pm
"A jet traveled with the wind for 2 hours and returned in 2 hours and 10 min. If the total trip is 2080 km, find the speeds of the jet and the wind."
If an object travels WITH the wind it moves faster. If it travels AGAINST the wind it moves slower.
Let J= jet speed and W=wind speed
The jet travelled the same distance both trips which is 2080/2 km = 1040 km
(J+W)2 = 1040
(J-W)(2 1/6) = 1040
J+W = 520
J-W(13/6) = 1040
J-W = 1040 * 6/13 = 480
2J = 1000
J = 500
W = 520-500 = 20
Jet speed is 500 km/hr and wind speed is 20 km/hour.
If an object travels WITH the wind it moves faster. If it travels AGAINST the wind it moves slower.
Let J= jet speed and W=wind speed
The jet travelled the same distance both trips which is 2080/2 km = 1040 km
(J+W)2 = 1040
(J-W)(2 1/6) = 1040
J+W = 520
J-W(13/6) = 1040
J-W = 1040 * 6/13 = 480
2J = 1000
J = 500
W = 520-500 = 20
Jet speed is 500 km/hr and wind speed is 20 km/hour.
2018-09-25 3:55 am
Let J and W be the speeds of the jet and the wind in km/hr
Outbound, the wind speed adds on to the jet’s natural speed in still air.
On the return journey the wind opposes, so the journey takes longer.
The distance there and distance back is the same; 1040 km
Express both trip distances as speeds * times
2J + 2W = 1040 ………………………………..(1)
2 hours and 10 mins is 13/6 hours
13/6J - 13/6W = 1040 ……………………….(2) … multiply (2) by 12/13
2J - 2W = 1040*12/13 = 960 ……………..(3)
J = (1040 + 960)/2 = 500 km/hr
W = (1040 - 960)/2 = 400 km/hr
Outbound, the wind speed adds on to the jet’s natural speed in still air.
On the return journey the wind opposes, so the journey takes longer.
The distance there and distance back is the same; 1040 km
Express both trip distances as speeds * times
2J + 2W = 1040 ………………………………..(1)
2 hours and 10 mins is 13/6 hours
13/6J - 13/6W = 1040 ……………………….(2) … multiply (2) by 12/13
2J - 2W = 1040*12/13 = 960 ……………..(3)
J = (1040 + 960)/2 = 500 km/hr
W = (1040 - 960)/2 = 400 km/hr
2018-09-25 3:24 am
Two equations, two unknowns:
each leg (there and back) is 1040 km
(J + W) * 2 = 1040
(J - W) * 2.167 = 1040
From 1: J + W = 520
From 2: J - W = 480
Add 1 and 2
2J = 1000
J = 500 km/h
W = 20 km/h
each leg (there and back) is 1040 km
(J + W) * 2 = 1040
(J - W) * 2.167 = 1040
From 1: J + W = 520
From 2: J - W = 480
Add 1 and 2
2J = 1000
J = 500 km/h
W = 20 km/h
2018-09-26 7:34 am
A jet traveled with the wind for 2 hours and returned in 2 hours and 10 min.
If the total trip is 2080 km, find the speeds of the jet and the wind.
With the wind it's travelling at an average speed of 1040/2 = 520 kmph.
Against the wind it's travelling 1040/(2 1/6) = 480 kmph.
Assuming the wind is constant.
Plane speed + wind speed = 520 kmph
Plane speed - wind speed = 480 kmph
Let's assume plane speed = p and wind speed = s
p + w = 520
p - w = 480
2w = 40
w = 20
So the plane is travelling at a windless speed of 500 kms per hour
and the wind speed is 20 kms per hour.
If the total trip is 2080 km, find the speeds of the jet and the wind.
With the wind it's travelling at an average speed of 1040/2 = 520 kmph.
Against the wind it's travelling 1040/(2 1/6) = 480 kmph.
Assuming the wind is constant.
Plane speed + wind speed = 520 kmph
Plane speed - wind speed = 480 kmph
Let's assume plane speed = p and wind speed = s
p + w = 520
p - w = 480
2w = 40
w = 20
So the plane is travelling at a windless speed of 500 kms per hour
and the wind speed is 20 kms per hour.
2018-09-25 6:07 am
_______________with_____against
distance (km)____2080_____2080
time (h)__________2_______13/6
speed (km/h)____1040 _____960
j + w = 1040
j - w = 960________add
2j = 2000
j = 1000 km/h_____jet speed
w = 40 km/h______wind speed
distance (km)____2080_____2080
time (h)__________2_______13/6
speed (km/h)____1040 _____960
j + w = 1040
j - w = 960________add
2j = 2000
j = 1000 km/h_____jet speed
w = 40 km/h______wind speed
2018-09-25 3:21 am
let x and y be the speeds of the jet and the wind.
speed = distance/time
converting time to minutes
leg 1: x+y = 2080/120
leg 2: x–y = 2080/130
2 equations 2 unknowns
120x + 120y = 2080
130x – 130y = 2080
multiply first by 130/120
130x + 130y = 2253.333
130x – 130y = 2080
add
260x = 4333.333
x = 16.67 km/min or 1000 km/hr
120(16.67) + 120y = 2080
y = (2080–120•16.67)/120 = 0.666667 km/min or 40 km/hr
speed = distance/time
converting time to minutes
leg 1: x+y = 2080/120
leg 2: x–y = 2080/130
2 equations 2 unknowns
120x + 120y = 2080
130x – 130y = 2080
multiply first by 130/120
130x + 130y = 2253.333
130x – 130y = 2080
add
260x = 4333.333
x = 16.67 km/min or 1000 km/hr
120(16.67) + 120y = 2080
y = (2080–120•16.67)/120 = 0.666667 km/min or 40 km/hr
2018-09-25 3:20 am
Assuming the same path for both trips, 1040 km in 2 hours means that they travelled at 520 km/hr on the leg with the wind and 479 km/hr against the wind
The equations are: (jet speed) + (wind speed) = 520
and (jet speed) - (wind speed) = 479
Subtract the two equations and you get 2 x (wind speed) = 40 km/hr or wind speed = 20 km/hr.
Hence jet speed = 500 km/hr
The equations are: (jet speed) + (wind speed) = 520
and (jet speed) - (wind speed) = 479
Subtract the two equations and you get 2 x (wind speed) = 40 km/hr or wind speed = 20 km/hr.
Hence jet speed = 500 km/hr
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