places a and b are 80 km apart from each other on a highway. A car starts from A and another from B at the same time. if they move in the same direction, they meet in 8 hours and if they move in the opposite direction, they meet in 1 hour 20 minutes. Find the speeds of the cars.
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Answers
Answer:
35 km/hr, 25 km/hr
Step-by-step explanation:
Speed of the first car which starts from A = x km /hr
Speed of the second car which starts from B = y km / hr
Distance between two places A and B is 80 km.
( i ) if the cars move in same direction
Relative speed of them = ( x + y ) km/hr
Time = 8 hr
d = 80 km
=> 8 = 80 / ( x + y )
=> x + y = 80 / 8
=> x + y = 10
( ii ) if two cars moving opposite direction
Relative speed = ( x - y ) km / hr
Time = 1 hr 20 minutes = (60 + 20) = 80
=> ( 80/60)
=> 4/3 hr
d = 80 km
=> 4/3 = 80 / ( x -y )
=> x - y = ( 80 × 3 ) / 4
=> x - y = 60
Add ( 1 ) and ( 2 ) , we get
=> 2x = 70
=> x = 35
Put x = 35 in ( 1 ) we get ,
y = 25
Therefore ,
Speed of the first car = x = 35 km/hr
Speed of the second car = 25 km /hr
Hope it helps!
Answer:
Speed of A = 35 km/h and Speed of B = 25 km/h or vice versa.
Step-by-step explanation:
Let speed of car A = x km/h
Let speed of car B = y km/h
We know, Distance=speed×time
Distance covered by A in 8 hrs = x × 8 = 8x km
Distance covered by B in 8 hrs = y × 8 = 8y km
Let they move in the same side of B.
According to question, 8x=8y+80
x=y+10.........(i)
We know, 1hr20mins=1+ 20/60 =4/3 hrs
Distance covered by A in 4/3 hrs = x ×4/3=4x/3km
Distance covered by B in 4/3 hrs = y ×4/3=4y/3km
So, 4x/3 + 4y/3 = 80
x+y=60.......(ii)
Using (i) and (ii),
y=25 km/h
x=25+10=35 km/h
So, Speed of A = 35 km/h
Speed of B = 25 km/h or vice versa
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