. 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 same direction they meet in 8 hrs and if they move in opposite direction they
meet in 1hr.20minutes. find speed of the car.
Answers
♕hello✌
answer:
⚘Let the speed of the first car which
starts from A = x km /hr
Speed of the second car which starts
from B = y km / hr
We know that,
______________________
Time = distance / speed
______________________
Distance between two places A and
B are 80km
d = 80 km
i ) if the cars move in same direction
Relative speed of them = ( x + y )
km/hr
Time = 8hr
d = 80km
8 = 80 / ( x + y )
x + y = 80 / 8
x + y = 10 ------( 1 )
ii ) if two cars moving opposite
direction,
Relative speed = ( x - y ) km / hr
Time = 1 hr 20 minutes
= ( 1 + 20 / 60 ) hr
= ( 80/60)
= 4/3 hr
d = 80km
4/3 = 80 / ( x -y )
x -y = ( 80 × 3 ) / 4
x - y = 60-----( 2 )
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 = 35km/hr
Speed of the second car = 25km /hr
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Answer:
Step-by-step explanation:
We can use the formula speed= distance/time so, we can keep the value as:
Distance =80 km
Time = 1hr20 mins
S= D/T
= 80/80 = 1km/min
80 mins because 1hr20 min was converted into mins.