Train A leaves station M at 7:20 AM and reaches station N at 2:20 PM on the same day. Train B leaves station N at 9:20 AM and reaches station M at 2:20 PM on the same day. Find the time when Trains A and B meet.

Correct option is A

Given:

Train A travels from M to N in 7:00 hours (from 7:20 AM to 2:20 PM)

Train B travels from N to M in 5:00 hours (from 9:20 AM to 2:20 PM)

Formula Used: 

Speed = $$\frac{\text{Distance}}{\text{Time}}$$

Solution:

Let the total distance between M and N be LCM(7, 5) = 35 units 

Speed of Train A = $$\frac{35}{7}$$​ = 5 units/hour

Speed of Train B = $$\frac{35}{5}$$​ = 7 units/hour

Since Train A starts at 7:20 AM and B at 9:20 AM, 

Distance covered by A by 9:20 AM = 2 × 5 = 10 units

Remaining distance = 35 − 10 = 25 units

Relative speed = 5 + 7 = 125 + 7 = 12 units/hour

Time to meet = $$\frac{25}{12} \approx 2.08 \text{ hours}$$​ = 2 hours 5 minutes

Add 2 hours 5 minutes to 9:20 AM = 11:25 AM