Aptitude Day 280

Problems on Time and Distance: 

1. Two trains start from P and Q respectively and travel towards each other at a speed of 30 km/hr and 20 km/hr respectively. By the time they meet, the first train has travelled 50 km more than the second. The distance between P and Q is:

Solution:

                  Let the distance travelled by 2^nd train be x and the 1^st train be x+50

                   x/20 = (x+50)/30

                   30x = 20x+1000

                    x = 100.

                    Distance between them = x+x+50 = 250 km.

2. The distance between 2 cities A and B is 220 km. A train starts from A at 10 AM and travels towards B at 50 km/hr. Another train starts from B at 11 AM and travels towards A at 70 km/hr. At what time do they meet?

Solution:

                  Consider they meet x hours after 10 AM

                  50x+70(x-1) = 220

                  By solving above equation, we get

                  x =29/12 = 2(5/12) = 2 hours 25 minutes.

                  They meet at 12.25 PM. (10 AM + 2 hours 25 minutes)