Ravi starts for his school at 8:20 a.m. on his bicycle. If he travels at a speed of 10km/h, then he reaches his school late by 8 minutes but on travelling at 16 km/h he reaches the school 10 minutes early. At what time does school start?

Solution:

Let x be the distance in km to the school and let t be the correct time in minutes to reach school, Hence,

At 10 km /h speed, Ravi Reaches 8 minutes late

x/10 = t + 8/60 --- (1) [8/60 to convert minutes into hours]

At 16 Km/h Ravi reaches 10 minutes early

x/16 = t - 10/60 --- (2) [10/60 to convert minutes into hours]

Comparing (1) and (2) we get

10t + 4/3 = 16t - 8/3

6t = 12/3

t = 2/3 hours or 40 minutes

The correct time of the start of the school is 9:00 am as Ravi reaches the school in 40 minutes.

✦ Try This: Ravi starts for his school at 8:20 a.m. on his bicycle. If he travels at a speed of 3km/h, then he reaches his school late by 10 minutes but on travelling at 5 km/h he reaches the school 12 minutes early. At what time does school start?

Let x be the distance in km to the school and let t be the correct time in minutes to reach school, Hence,

At 3 km /h Ravi Reaches 8 minutes late

x/3 = t + 8/60 --- (1) [8/60 to convert minutes into hours]

At 5 Km/h Ravi reaches 10 minutes early

x/5 = t - 10/60 --- (2) [10/60 to convert minutes into hours]

Comparing (1) and (2) we get

3t + 4/5 = 5t - 5/6

2t = 4/5 + 5/6

2t = 49/30

t = 49/60 hours or 49 minutes

The correct time of the start of the school is 9:09 am as Ravi reaches the school in 49 minutes.

☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 13

NCERT Exemplar Class 8 Maths Chapter 10 Problem 90

Ravi starts for his school at 8:20 a.m. on his bicycle. If he travels at a speed of 10km/h, then he reaches his school late by 8 minutes but on travelling at 16 km/h he reaches the school 10 minutes early. At what time does school start?

Summary:

Ravi starts for his school at 8:20 a.m. on his bicycle. If he travels at a speed of 10km/h, then he reaches his school late by 8 minutes but on travelling at 16 km/h he reaches the school 10 minutes early. The school starts at 9:00 am

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