A train covered a certain distance at a uniform speed. if the speed of the train had been 6 km/hr faster, it would have taken 4 hour less time than the scheduled time and if the speed of the train were slower by 6 km/hr, the train would have taken 6 hr more than the scheduled time. the length of the journey was:
Answers
Answered by
839
Let x km/hr be the speed of train
Let y be the time taken by the train
Distance = speed x time
= x y
To form the first equation let us consider the given information from the question that is If the train had been 6 km/hr faster,it would have taken 4 hours less than the scheduled time.
it clearly says that speed is increased by 6 and time is reduced by 4
So , (x + 6) (y - 4) = x y
x y - 4 x + 6 y - 24 = x y
x y - x y - 4 x + 6 y = 24
- 4 x + 6 y = 24
divided by (-2) => 2 x - 3 y = -12 ----- (1)
To form the second equation let us consider the given information from the question that is If the train were slower by 6km/hr, then it would have taken 6 hours more than the scheduled time.
it clearly says that speed is reduced by 6 and time is increased by 6
So , (x - 6) (y + 6) = x y
x y + 6 x - 6 y - 36 = x y
x y - x y + 6 x - 6 y = 36
6 x - 6 y = 36
divided by (6) => x - y = 6 ----- (2)
2 x - 3 y = -12
(2) x 2 => 2 x - 2 y = 12
(-) (+) (-)
---------------
- y = -24
y = 24
Now we have to apply the value of y in the first equation to get value of x
Substitute y = 24 in the first equation we get
2 x - 3 (24) = -12
2 x - 72 = -12
2 x = -12 + 72
2 x = 60
x = 60/2
x = 30
Speed of the train = 30 km/hr
Time taken by the train = 24 hours
Distance covered by the train = x y = 30 x 24 = 720 km
Verification:
2 x – 3 y = -12
2(30) - 3(24) = -12
60 - 72 = -12
-12 = -12
Hope this helps you
Let y be the time taken by the train
Distance = speed x time
= x y
To form the first equation let us consider the given information from the question that is If the train had been 6 km/hr faster,it would have taken 4 hours less than the scheduled time.
it clearly says that speed is increased by 6 and time is reduced by 4
So , (x + 6) (y - 4) = x y
x y - 4 x + 6 y - 24 = x y
x y - x y - 4 x + 6 y = 24
- 4 x + 6 y = 24
divided by (-2) => 2 x - 3 y = -12 ----- (1)
To form the second equation let us consider the given information from the question that is If the train were slower by 6km/hr, then it would have taken 6 hours more than the scheduled time.
it clearly says that speed is reduced by 6 and time is increased by 6
So , (x - 6) (y + 6) = x y
x y + 6 x - 6 y - 36 = x y
x y - x y + 6 x - 6 y = 36
6 x - 6 y = 36
divided by (6) => x - y = 6 ----- (2)
2 x - 3 y = -12
(2) x 2 => 2 x - 2 y = 12
(-) (+) (-)
---------------
- y = -24
y = 24
Now we have to apply the value of y in the first equation to get value of x
Substitute y = 24 in the first equation we get
2 x - 3 (24) = -12
2 x - 72 = -12
2 x = -12 + 72
2 x = 60
x = 60/2
x = 30
Speed of the train = 30 km/hr
Time taken by the train = 24 hours
Distance covered by the train = x y = 30 x 24 = 720 km
Verification:
2 x – 3 y = -12
2(30) - 3(24) = -12
60 - 72 = -12
-12 = -12
Hope this helps you
Answered by
236
★★☆☆Let x km/hr be the speed of train .
Let y be the time taken by the train .
Distance =speed × time
Xy = Putting in 1 equation
So, (x+6) (y-4)=xy
xy-xy-4x+6y=24
-4x+6y=24 -- this is the 1 equation
Divided by (-2) 2x-3y= -12
there is second equation solve
So, (x-6) (y+6)=xy
xy+6x-6y-36=xy
xy-xy+6x-6y=36
6x-6y=16
Divided by 6 x-y=6--- this is the 2 equation
2x-3y=-2
(2)×2---2x-2y=12
-y=-24
y=24
Then, substitute method solve
y=24 in---1 equation
2x-72 =-12
2x=-12+72
2x=60
x=60/2
x=30
Then, we find the spped of he train = 30km
Time taken by he train =24km
Distance is coverd by train =xy
=30×24=720
2x-3y=-12
2 (30)-3 (24)=-12
60-72=-12
-12=-12
=1
Hope this solution is help u♡♡
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