an express train makes a run of 240 km at a certain speed. another train whose speed is 12km/hr less takes an hour longer to cover the same distance. find the speed of the express train in km/hr.
60 km/hour
speed of express ---- x km/h
speed of slow train -- x - 12 km/h
solve for x
240/(x-12) - 240/x = 1
(saying: the difference in their times = 1 hr
and time = distance/rate )
How can it be 48 ,it must be less than the other train
I donot understand
v t = 240 so t = (240/v)
(v-12) (t+1) = 240
====================
v t - 12 t + v - 12 = 240
or
v + vt -12 t = 252
substitute
v +240 - 12(240/v) = 252
v^2 - 12 v - 2880 = 0
(v-60)(v+48) = 0
v = -48 simply will not do
so
v = 48 km/hour
Even now i donot understand
Ya the answer is right u can check it
Ya that's right u all can check it
To find the speed of the express train, we can set up an equation based on the given information.
Let's assume the speed of the express train is x km/hr.
The other train is traveling at a speed of (x - 12) km/hr.
We are given that the distance covered by both trains is 240 km.
Using the formula: distance = speed × time, we can create two equations based on the information given:
For the express train:
240 = x × time1
For the other train:
240 = (x - 12) × (time1 + 1)
Since we are looking for the speed of the express train, we want to eliminate the time variable. To do this, we need to equate the times in both equations.
Given that the second train takes an hour longer to cover the same distance, we have:
time1 + 1 = time1
Substituting this back into our equations, we get:
240 = x × time1
240 = (x - 12) × time1
Now, notice that we have two equations with the same time1 variable. We can equate these two equations:
x × time1 = (x - 12) × time1
Since time1 is common in both sides of the equation, we can cancel it out:
x = x - 12
Simplifying the equation, we get:
12 = 0
This equation has no solution when simplified. It means that we have reached an inconsistency, and there might be an error in the given information or the problem itself. Please double-check the problem statement or provide additional information if possible.