Question

Chennai is at a distance of 560 km from mumbai. A train starts from mumbai to chennai at 6
a.M. With a speed of 40 kmph. Another train starts from chennai to mumbai at 7
a.M. With a speed of 60 kmph. At what distance from mumbai will the two trains be at the point of crossing?

Answer 1

Explanation:

Given Chennai is at a distance of 560 km from Mumbai. A train starts from Mumbai to Chennai at 6  a.M. With a speed of 40 kmph. Another train starts from Chennai to Mumbai at 7  a.M. With a speed of 60 kmph. At what distance from Mumbai will the two trains be at the point of crossing?

We know that time from 6 a.m. to 7 a.m. is 1 hour.

So distance from Mumbai at point of meeting will be

                                                                   = s1 (d + s2T / s1 + s2) km

                                                                  = 40 (560 + 60 x 1 / 40 + 60) km

                                                                     = 40 x 620 / 100

                                                                    = 248 km

  Now we need to find time of meeting

                                                         = (d + s2T / s1 + s2)

                                                         = (560 + 60 x 1 / 40 + 60 )

                                                          = 620 / 100

                                                           = 31 / 5 h

                                                            = 6.2 hrs (0.2 x 60 = 12 min)

So 6 hrs 12 min after 6 a.m.

Now the point of crossing will be at 12.12 noon.

Answer 2

Explanation:

any direct method is possible? without using formula