Q6 of 40 Page 92

Places A and B are 100 km apart on a highway. One car starts from A and another from B at the same time at different speeds. If the cars travel in the same direction, they meet in 5 hours. If they travel towards each other, they meet in 1 hour. What are the speeds of the two cars?

Let the speed of faster car = x km/h

Speed of slower car = y km/h


Relative speed when both car travels in same direction = x-y


If the cars travel in the same direction, they meet in 5 hours.



Total distance = 100 km


x-y = ⇒ x-y = 20 …1


Relative speed when both car travels in different direction = x + y


If they travel towards each other, they meet in 1 hour.


x + y = 100 …2


Adding Eq. 1 and 2


x-y = 20


x + y = 100


2x = 120


x =


substituting x = 60 in eq. 2


60 + y = 100


y = 100-60


y = 40 km


Speed of the faster car = 60km/h


Speed of the slower car = 40km/h


More from this chapter

All 40 →
4

The taxi charges in Hyderabad are fixed, along with the charge for the distance covered. For a distance of 10 km., the charge paid is D220. For a journey of 15km. the charge paid is D310.

i. What are the fixed charges and charge per km?


ii. How much does a person have to pay for travelling a distance of 25 km?

 5

A fraction becomes equal to if 1 is added to both numerator and denominator. If however, 5 is subtracted from both numerator and denominator, the fraction becomes equal to What is the fraction?

 7

Two angles are complementary. The larger angle is 3o less than twice the measure of the smaller angle. Find the measure of each angle.

 8

An algebra textbook has a total of 1382 pages. It is broken up into two parts. The second part of the book has 64 pages more than the first part. How many pages are in each part of the book?