IMHO C is the correct answer.
Statement 1: The distance between Patna and Allahabad is 250km. Prem travels at 50 km.h, and Ramesh travels at 25 km/h.
Relative speed when traveling towards each other is: 50 + 25 = 75 km/h;
Time to meet = Distance/Relative speed = 250/75 = 10/3 hours (3 hours and 20 min);
However, this calculation assumes both started at the same time, which is not stated. Without knowing the starting times, Statement 1 alone is insufficient.
Statement 2: Prem started at 5:00 am from Patna and reached Allahabad at 11:00 am. Ramesh started at 7:00 am and reached Patna at 3:00 pm.
From this, we can calculate the speeds:
Prem's travel time: 5 am to 11 am, which is 6 hours. Therefore, 250 km/6 hours = 41.6 km/h;
Ramesh's travel time 7 am to 3 pm, which is 8 hours. Therefore, 250 km/8 hours = 31.2 km/h;
However, we don't know their meeting time because we don't know how far each traveled before meeting. So, Statement 2 alone is insufficient.
Using the speeds from Statement 1 and starting times from Statement 2:
Prem starts at 5 am, and Ramesh starts at 7 am, giving Prem a 2-hour head start. In 2 hours, Prem travels 50 km/h * 2 hours = 100 km. So, at 7 am Prem is 100 km away from Patna;
At 7 am, the distance between them is 250 - 100 = 150 km;
They are now traveling towards each other at a relative speed of 50 + 25 = 75 km/h;
Time to meet: 150/75 = 2 hours. Therefore, they meet at 7 am + 2 hours = 9:00 am. Hence, both statements together are sufficient to answer the question, but neither alone is sufficient.