49 Views

Question : A train travels at a speed of 18 m/s in the first 5 minutes, covers 7.5 km in the next 10 minutes and covers 12 km in another 10 minutes. What is its average speed (in km/h, rounded off to 1 decimal place) for the entire journey?

Option 1: 59.8

Option 2: 71.2

Option 3: 45.7

Option 4: 64.6


Team Careers360 9th Jan, 2024
Answer (1)
Team Careers360 11th Jan, 2024

Correct Answer: 59.8


Solution : Speed of train in the first 5 minutes = 18 m/s
Distance travelled by train in next 10 mins = 7.5 km
Distance travelled by train in next 10 mins = 12 km
Distance = Speed $\times$ Time
Distance travelled by train in the first 5 mins = $18\times (5\times 60)$ = 5400 m = 5.4 km
Total time taken = $\frac{5}{60} + \frac{10}{60} + \frac{10}{60} = \frac{25}{60} = \frac{5}{12}$ hr
Average Speed = $\frac{\text{Total distance}}{\text{Total time taken}}$
$= \frac{(5.4 + 7.5 + 12)\times 12}{5} = \frac{24.9\times 12}{5}=\frac{298.8}{5} = 59.8$ km/hr
Hence, the correct answer is 59.8.

SSC CGL Complete Guide

Candidates can download this ebook to know all about SSC CGL.

Download EBook

Know More About

Related Questions

TOEFL ® Registrations 2024
Apply
Accepted by more than 11,000 universities in over 150 countries worldwide
Manipal Online M.Com Admissions
Apply
Apply for Online M.Com from Manipal University
View All Application Forms

Download the Careers360 App on your Android phone

Regular exam updates, QnA, Predictors, College Applications & E-books now on your Mobile

150M+ Students
30,000+ Colleges
500+ Exams
1500+ E-books