Ayush and Ranjan are standing at a distance of 20 km. They start walking towards each other. After how much time will they meet if they keep walking?

(I): Ayush and Ranjan walk at the speed of 2 km/hr and 3 km/hr respectively.
(II): The speed of walking of Ayush to Ranjan is 2 : 3.

Ayush and Ranjan are 20 km apart and walk towards each other. When will they meet?

Statement (I):
Ayush walks at 2 km/hr and Ranjan at 3 km/hr.
Combined speed = 2 + 3 = 5 km/hr
Time = 20 ÷ 5 = 4 hours

So, statement (I) alone is sufficient.

Statement (II):
Speed ratio of Ayush to Ranjan is 2 : 3.
Actual speeds are not known, so time cannot be calculated.

So, statement (II) alone is not sufficient.

Thus, correct option is (a).