Question

Places A and B are 80km apart from each other on a highway. A car starts from A and another from B at the same time. If they move in same direction they meet in 8hours and if they towards each other they meet in 1 hour 20 minutes. Find the speed of cars.


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class 10 question

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Answer 1

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⭐⭐⭐hey mate here your answer ⭐⭐⭐

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Let the speed of car starting from A be 'x' km/h

and

speed of car starting from B be 'y' km/h.

Total distance=80 km

Also 1 hour 20 mins= 4/3 hour

As per given condition, When car moves in same direction,

Distance travelled by y= 8y km

Distance travelled by x= 8x= 80+8y

Now, Equation formed is 8x=80+8y

=> 8x-8y=80

=> x-y=10 ----(1)

Similarly, For opposite direction,

Distance travelled by x= (4/3)x

Distance travelled by y= (4/3) y

Also total distance covered= 4/3*x+4/3y

=> 80= 4x+4y/3

=> 240= 4x+4y

=> 60=x+y ----(2)

Solving Equation (1) and (2)

60=x+y ----(2)

x-y=10 ----(1)

=> x= 10+y ----(3)

Substituting the value of (3) in (2) we get,

60= 10+y+y

=> 60-10=2y

=> 50=2y

=> 25=y

Also, x=10+y=> x= 10+25=> x=35

Therefore Speed of car starting from A is 35km/h

Speed of car starting from B is 25km/h

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hope its helpful☺

Answer 2

Distance between A and B= 80

let A speed be a

let B speed be b

If they move in same direction

then relative velocity = a - b

Velocity = a-b = distance/time = 80/8 = 10

if they move in opp.direction

Relative velocity = a+b

a+ b= 80/ 4/3 = 60

a- b= 10

Add

2a = 70

a= 35

a - b= 10

b= a-10= 35 -10= 25

So speed of cars are 35 and 25