Overtaking trains.

Algebra Level 2

The passenger train leaves the train depot 2 hours after a freight train left the same depot. The freight train is traveling 20 mph slower than the passenger train. Find the rate of passenger train, if the passenger train overtakes the freight train in three hours.

50mph 45mph 40mph 60mph

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

10 solutions

Akshat Mantri
Apr 20, 2014

Let the speed of the train be x . Then, the speed of the freight train would x-20 , since it was going 20 mph slower than the train. Now, it is said that the freight train left 2 hours earlier than the train. After 2 hours, the train then started moving. Hence, the train travelled 3 hours in total, and the freight train travelled for 2+3= 5 hours . Therefore, the equation is formed:

3(x) = 5(x-20) , which is solved further as

3x = 5x-100

-2x = -100

x = -100/-2

x = 100/2

x = 50

Therefore, x (the speed of the train)= 50mph. The answer is hence 50 mph

Vishal Antony
Apr 20, 2014

relative velocity = 20mph. hence initial distance between them = 20*3 = 60miles. hence velocity of F is 60/2 = 30. hence velocity of P is 30+20 = 50.

Himanshu Shekhar
Apr 20, 2014

lets tale speed of passenger train to be v,then speed of freight train is (v-20),the eqn would become- 3v=2(v-20)+3(v-20)

Jihan Ryeosomnia
Jan 30, 2016

3x=5(x-20) 3x=5x-100 3x-5x= -100 -2x = -100 X= 50

Kevin Patel
Apr 29, 2014

As distance covered by both trains at the point of meeting is equal, If 'd' is distance covered, d1=d2 and gets cancelled we get, 5*(s-20) = 3s 5s-100 = 3s 2s-10 = 0 2s = 100 s=50 mph

Shadman R.
Apr 27, 2014

Firstly consider "x" as the speed of the passenger train. That means the speed of the freight train, which is 20 mph slower, must be "x-20". The passenger train overtakes the freight train after 3 hours and also the passenger train starts 2 hours after the freight train. This means that the freight train has already traveled for 3+2= 5 hours. Because the passenger train over take after 3 hours that means the distance covered by the passenger train in 3 hours is equal to the distance covered by the freight train in 5 hours. Manipulating this info we can say : 3x= 5 (x-20) 3x= 5x-100 100 = 5x-3x 100= 2x 100/2 = x therefore, x = 50 because "x" was the speed of the passenger train, therefore the passenger train was traveling at 50 mph

Rathin Gayen
Apr 22, 2014

let they meet X km apart from the staring point,then faster train speed=X/3,& slower train speed=X/5, X/3-X/5=20,x=150 and faster train speed=150/3=50

Aniket Mishra
Apr 22, 2014

let the speed of passenger train be v,then speed of freight train =v-20 now,distance travelled by freight train in 5 hrs=(v-20) 5.............(1) and,same distance travelled by passenger train in 3 hrs=3v...........(2) from (1) and (2) we get, (v-20) 5=3v v=50mph

Cameron Hardman
Apr 21, 2014

Time and speed are inversely proportional due to constant distant. Time decreases by 3/5 hence speed increases by 2/5. As we know the speed is 20mph more than the freight train's speed, x, and is 2/5 more (5/3(x)). Thus x+20=(5/3)x. Solved for x gives x=50. Answer is thus 50mph

Vi Le
Apr 21, 2014

Let the distance the both trains get until the passenger train takes over be S. Let the speed of the passenger train be v1. Let the speed of the freight train be v2. v1 = S/3 v2 = S/(3+2) =S/5 v1 - v2 = S/3 - S/5 = 2S/15 = 20 Therefore, S = 150. Therefore, v1 = 150/3 = 50

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...