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Ranjeet drives his car at an average spe...

Ranjeet drives his car at an average speed of 50 km/hr and reaches his destination in 8 hours. Rahman covers the same distance in 5 hours. If Ranjeet increases his speed by 10 km/hr and Rahman increases his speed by 20 km/hr, then what will be the difference in time taken by them to reach their destination?

A

2 hours 30 minutes

B

3 hours 40 minutes

C

3 hours 20 minutes

D

2 hours 40 minutes

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem step by step, let's break it down: ### Step 1: Calculate the distance Ranjeet travels. Ranjeet drives his car at an average speed of 50 km/hr for 8 hours. To find the distance, we use the formula: \[ \text{Distance} = \text{Speed} \times \text{Time} \] Substituting the values: \[ \text{Distance} = 50 \, \text{km/hr} \times 8 \, \text{hours} = 400 \, \text{km} \] ### Step 2: Calculate Rahman's speed. Rahman covers the same distance of 400 km in 5 hours. To find Rahman's speed, we use the formula: \[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} \] Substituting the values: \[ \text{Speed} = \frac{400 \, \text{km}}{5 \, \text{hours}} = 80 \, \text{km/hr} \] ### Step 3: Determine the new speeds after the increase. Ranjeet increases his speed by 10 km/hr: \[ \text{New Speed of Ranjeet} = 50 \, \text{km/hr} + 10 \, \text{km/hr} = 60 \, \text{km/hr} \] Rahman increases his speed by 20 km/hr: \[ \text{New Speed of Rahman} = 80 \, \text{km/hr} + 20 \, \text{km/hr} = 100 \, \text{km/hr} \] ### Step 4: Calculate the time taken by Ranjeet with the new speed. Using the formula for time: \[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \] For Ranjeet: \[ \text{Time} = \frac{400 \, \text{km}}{60 \, \text{km/hr}} = \frac{400}{60} = \frac{20}{3} \, \text{hours} \] This is approximately 6 hours and 40 minutes. ### Step 5: Calculate the time taken by Rahman with the new speed. For Rahman: \[ \text{Time} = \frac{400 \, \text{km}}{100 \, \text{km/hr}} = 4 \, \text{hours} \] ### Step 6: Find the difference in time taken by Ranjeet and Rahman. To find the difference: \[ \text{Difference} = \text{Time taken by Ranjeet} - \text{Time taken by Rahman} \] \[ \text{Difference} = \left(6 \, \text{hours} + 40 \, \text{minutes}\right) - 4 \, \text{hours} \] Convert 40 minutes to hours: \[ 40 \, \text{minutes} = \frac{40}{60} \, \text{hours} = \frac{2}{3} \, \text{hours} \] So, \[ \text{Difference} = \left(6 + \frac{2}{3}\right) - 4 = 2 + \frac{2}{3} = 2 \, \text{hours} + 40 \, \text{minutes} \] ### Final Answer: The difference in time taken by Ranjeet and Rahman to reach their destination is **2 hours and 40 minutes**. ---
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