Ranjeet starts his journey to a certain place by car at 9 a.m. and reaches the place at 1p.m., if he drives the car at a speed of 30 km/hr. By how much should he increase thespeed so that he can reach the place by 12 noon?

To find out how much Ranjeet should increase his speed in order to reach the place by 12 noon, we need to calculate the time difference between his current arrival time (1 p.m.) and the desired arrival time (12 noon).

Step 1: Calculate the time taken by Ranjeet to reach the place at his current speed. Ranjeet starts his journey at 9 a.m. and reaches the place at 1 p.m., which means he travels for a total of 4 hours.

Step 2: Calculate the distance traveled by Ranjeet. We know that speed = distance/time. Rearranging the formula, we get distance = speed * time. Given that Ranjeet drives at a speed of 30 km/hr and travels for 4 hours, we can calculate the distance as follows: Distance = 30 km/hr * 4 hrs = 120 km.

Step 3: Calculate the time difference between the desired arrival time and the current arrival time. The desired arrival time is 12 noon, which means Ranjeet needs to reach the place 3 hours earlier than his current arrival time (1 p.m. - 12 noon = 1 hour). Therefore, the time difference is 3 hours.

Step 4: Calculate the increased speed required to cover the distance in the reduced time. To calculate the increased speed, we need to divide the distance by the reduced time. Increased speed = distance/time. Given that the distance is 120 km and the reduced time is 3 hours, we can calculate the increased speed as follows: Increased speed = 120 km / 3 hrs = 40 km/hr.

Therefore, Ranjeet should increase his speed by 10 km/hr (from 30 km/hr to 40 km/hr) in order to reach the place by 12 noon.