Select the correct answerA boy walking at a speed of 20kmph reaches his school 15min late. Next time at a speed of 25kmph reaches his school 10m early find the usual time to reach the school?Options150min120min110min144min

Let's solve this step by step:

1. First, we need to understand that the time difference between the two scenarios is the boy being 15 minutes late and 10 minutes early, which is a total of 25 minutes.

2. We also know that the difference in speed between the two scenarios is 5 km/h (25km/h - 20km/h).

3. We can use the formula for time, which is distance divided by speed. In this case, the distance to the school remains the same in both scenarios, so we can set up the following equation:

   (Distance/20) - (Distance/25) = 25/60 (we convert the minutes into hours since the speed is given in km/h)

4. To solve this equation, we can first find a common denominator for the fractions, which is 100 in this case:

   (5Distance/100) - (4Distance/100) = 25/60

5. Simplifying this gives:

   Distance/100 = 25/60

6. Solving for Distance gives:

   Distance = 25/60 * 100 = 41.67 km

7. Now, we can find the usual time it takes for the boy to reach school by dividing the distance by his usual speed:

   Time = Distance/Speed = 41.67 km / 20 km/h = 2.083 hours

8. Converting this time into minutes gives:

   Time = 2.083 hours * 60 minutes/hour = 125 minutes

So, the correct answer is not in the options given. The boy usually takes 125 minutes to reach school.