Two cities B and D are 320 km apart. A motorcyclist travels from B to D at 7 am at a speed of 40 km/hr. Another rider starts from D to B at 8 am at the speed of 30 km/hr. Find out at what time they will cross each other.
1
1 : 30 pm
2
12 pm
3
10 am
4
11 am