1 View

Question : Points 'A' and 'B' are 70 km apart on a highway. A car starts from 'A' and another from 'B' at the same time. If they travel in the same direction, they meet in 7 hours, but if they travel towards each other, they meet in one hour. Find the speed of the two cars (in km/hr).

Option 1: 20, 30

Option 2: 40, 30

Option 3: 30, 50

Option 4: 20, 40


Team Careers360 25th Jan, 2024
Answer (1)
Team Careers360 26th Jan, 2024

Correct Answer: 40, 30


Solution : Let the speed of the car starting from A be $x$ km/hr and that from B be $y$ km/hr. ($x>y$)
In opposite direction, relative speed = $(x+y)$ km/hr
In same direction, relative speed = $(x-y)$ km/hr
Distance = 70 km
⇒ $\frac{70}{x-y}$ = 7 [Use: Time = $\frac{\text{Relative Distance}}{\text{Relative Speed}}$]
⇒ $x-y$ = 10 --------------(i)
Also, $\frac{70}{x+y}$ = 1 [Use: Time = $\frac{\text{Relative Distance}}{\text{Relative Speed}}$]
⇒ $x+y$ = 70 --------------(ii)
Adding (i) and (ii),
$2x$ = 80
⇒ $x$ = 40 km/hr
Subtracting (i) from (ii),
$2y$ = 60
⇒ $y$ = 30 km/hr
Hence, the correct answer is 40, 30.

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