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Places A and B are 160 km apart on a highway. One car starts from A and another from B at the same time. If the cars travel in the same direction at different speeds, they meet in 8 hours, but if they travel towards each other, they meet in 2 hours. What are the speeds of the two cars?

Sol .

Let the speed of 1st car starting from place A = x km/hr
and the speed of 2nd car starting from place B = y km/hr
When two cars travel in the same direction
Distance covered by 1st car in 8 hours
= 160 km + Distance covered by 2nd car
8x = 8y + 160 …( Q Distance = Speed time)
x = y + 20 …(i) (Dividing both sides by 8)
When two cars travel towards each other
2x + 2y = 160 …( D = S T)
x + y = 80 …(Dividing both sides by 2)
y + 20 + y = 80 …[From (i)]
2y = 80 – 20 = 60

From (i), x = 30 + 20 = 50
Speed of car starting from place A = 50 km/hr
and speed of car starting from place B = 30 km/hr.

Q. 18. Find the roots of the equation :

Sol .

Mathematics 2009 Question Papers Class X
Delhi		Outside Delhi		Compartment Delhi		Outside Delhi		Foreign
	Set 1 (PDF)		Set 1 (PDF)		Set 1		Set 1		Set 1 (PDF)
					Set 2		Set 2
					Set 3		Set 3