The ratio of Arif's driving speed and that of Babu's is 2:3. If Arif starts at 7:15 am from point A to Point B and Babu starts from 8:15 am and both reach at 10:00 am and the distance between A and B is 42 km what is the driving speed of Babu km/hour?

Explanation: Distance \(D = 42\) km. Arif's start time: 7:15 am. Arif's end time: 10:00 am. Arif's travel time (\(T_A\)) = 10:00 - 7:15 = 2 hours 45 minutes = \(2.75\) hours. Babu's start time: 8:15 am. Babu's end time: 10:00 am. Babu's travel time (\(T_B\)) = 10:00 - 8:15 = 1 hour 45 minutes = \(1.75\) hours. Babu's speed (\(S_B\)) = \(\frac{D}{T_B} = \frac{42}{1.75}\). \(1.75 = \frac{7}{4}\). \(S_B = \frac{42}{\frac{7}{4}} = 42 \times \frac{4}{7} = 6 \times 4 = 24\) km/hour. **However, the provided solution calculates it differently:** As time is inversely proportionate to speed it takes Arif 3 hours and Babu 2 hours. So babus speed is \(42/2=21 \text{ km/hr}\)". This implies an error in the given question or the provided solution