Places A and B
are 100 km apart on a highway. One car starts from A and another from B at the
same time. If the cars travel in the same direction at different speeds, they meet
in 5 hours. If they travel towards each other, they meet in 1 hour. What are
the speeds of the two cars?
Let speed of
faster car = x Km/ h
Speed of
slower car = y km /h
Relative speed
when both car travels in same direction = x - y
If the cars
travel in the same direction at different speeds, they meet in 5 hours
Speed =
distance/ time
Total
distance = 100 km
Speed x – y =
100/5
X – y = 20
Add y both
side we get
X = 20 + y …(1)
Relative speed
when both car travels in opposite direction = x + y
If they travel
towards each other, they meet in 1 hour.
Speed =
distance/ time
Total
distance = 100 km
Speed x + y = 100/1
Plug the value
of x form equation first we get
20 + y + y =
100
2y = 80
Y = 40
Plug the value
of y in equation first we get
X = 20 + 40
X = 60
Hence speeds are 40 Km /h and 60 Km /h
Thanks that's really helpful
ReplyDeleteVery useful!!!! Keep it up..
ReplyDeleteVery useful!!!! Keep it up..
ReplyDeletewhy did we take x-y as realtive speed
ReplyDeleteHow can the cars meet if they are travelling in same direction at different speeds
ReplyDeleteTake the example of athletics
DeleteIf car speed is 5 kmh and others is 1 kmh so the first one can easily over take the slower one after some rime
DeleteIf the cars meets in the same direction how thet meet
ReplyDelete@Rajat, relative speed should be the diff of two
ReplyDeleteWhat is relative speed?
ReplyDeleteWhen they travel in same direction how will the distance become 100 meter??
ReplyDeleteExactly how?
DeleteWhy the distance in first increase?
ReplyDelete