10 Views

Question : A man covers half part of a certain distance at 60 km/hr. He covers 40% of the remaining distance at the speed of 12 km/hr and covers the rest of the distance at the speed of 18 km/hr. What is his average speed for the entire journey?

Option 1: 24 km/hr

Option 2: $\frac{58}{3}$ km/hr

Option 3: 36 km/hr

Option 4: 40 km/hr


Team Careers360 17th Jan, 2024
Answer (1)
Team Careers360 24th Jan, 2024

Correct Answer: 24 km/hr


Solution : Let the total distance be 100 km.
Half distance = $\frac{100}{2}$ = 50 km
Speed = 60 km/hr
Time taken to cover half the distance = $\frac{50}{60}$ = $\frac{5}{6}$
Remaining distance = 50 km
Distance = 40% of the remaining distance = $\frac{40}{100}×50$ = 20 km
Speed = 12 km/hr
Time taken to cover 40% of the remaining distance = $\frac{20}{12}$ = $\frac{5}{3}$
Distance = 60% of the remaining distance = $\frac{60}{100}×50$ = 30 km
Speed = 18 km/hr
Time taken to cover 60% of the remaining distance = $\frac{30}{18}$ = $\frac{5}{3}$
Average speed = $\frac{\text{total distance}}{\text{total time}}$
= $\frac{100}{\frac{5}{6}+\frac{5}{3}+\frac{5}{3}}$
= $\frac{100}{\frac{25}{6}}$
= 24 km/hr
Hence, the correct answer is 24 km/hr.

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