Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
A man in a train traveling at 30 km/hr notices that a train going in the opposite direction passes him in 9 seconds. If the length of this train is 200m, find its speed?
 2 years ago
 2 years ago
A man in a train traveling at 30 km/hr notices that a train going in the opposite direction passes him in 9 seconds. If the length of this train is 200m, find its speed?
 2 years ago
 2 years ago

This Question is Closed

satellite73Best ResponseYou've already chosen the best response.0
solve \[200=(30+r)9\] for r
 2 years ago

GoBlueBest ResponseYou've already chosen the best response.0
distance=rate x time The train's relative speed is 200/9 m/s=80 km/hr Speed=8030=50 km/hr
 2 years ago

siddharthBest ResponseYou've already chosen the best response.2
Let the other train's speed be v km/hr. Now, if we consider the man to be stationary (his frame of reference), the other train will be travelling at 30+v km/hr in the opposite direction. So, other train travels 200m in 9 seconds. Distance = speed * time 200/1000 km = (30+v) km/hr * 9/3600 hrs 20 = (30+v)/4 v = 50 km /hr
 2 years ago

manoj12Best ResponseYou've already chosen the best response.0
Hello, siddharth, but 200/1000 is 0.2
 2 years ago

siddharthBest ResponseYou've already chosen the best response.2
I did some simplification: \[\frac{200}{1000} = \frac{9(30+v)}{3600}\] multiply both sides by 1000: \[200 = \frac{9(30+v)}{3600} \times 1000\] \[200 = \frac{9(30+v)}{36} \times 10\] divide both sides by 10 \[20 = \frac{9(30+v)}{36} \]
 2 years ago
See more questions >>>
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.