Correct Answer - Option 4 : 9.00 a.m.

**Given :**

Two stations A and B are 80 km apart

Train from A starts at 7 a.m with speed of 20 kmph

Train from B starts at 8 a.m with speed of 40 kmph

**Concept used :**

Relative speed

If vehicles are moving in opposite direction then speeds are added

if vehicles are moving in same direction then speeds are subtracted

**C****alculations :**

Train A starts at 7 a.m with speed of 20 kmph

Distance covered by train in 1 hour = 20 × 1 (Distance = speed × time)

⇒ 20 km

Now at 8 a.m distance between stations = 80 - 20 = 60 km

Now time taken after 8 a.m when both trains will meet = (Distance/speed)

⇒ 60/(20 + 40) (speeds are added because they are moving in opposite direction)

⇒ 60/60

⇒ 1 hour

Train will meet 1 hour after 8 a.m

∴ **Both the trains will meet at 9 a.m**