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 they travel in the same directiin, they meet in 8hrs. But, if they travel towqrds earch other, they meet in 2 hers. Find the speed of each car.
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Answered by
272
as we know, total distance= speed *time
Here, total distance is 160km
we take the speed of first car as x km/hr
and the speed of 2nd car be y km/hr
total speed in first case = (x+y) km/hr
total time = 8 hrs
d=st
160=(x+y)*8
which gives
x+y=20 _______(1)
2nd case
total speed = (x-y) km/hr
total time= 2hrs
160 = (x-y)*2
that gives
x-y=80________(2)
subtracting eq 1 from 2
x-y=80
x-y=20
- + -
-2y=-60
y =30km/hr
x-y=20
x=50km/hr
Here, total distance is 160km
we take the speed of first car as x km/hr
and the speed of 2nd car be y km/hr
total speed in first case = (x+y) km/hr
total time = 8 hrs
d=st
160=(x+y)*8
which gives
x+y=20 _______(1)
2nd case
total speed = (x-y) km/hr
total time= 2hrs
160 = (x-y)*2
that gives
x-y=80________(2)
subtracting eq 1 from 2
x-y=80
x-y=20
- + -
-2y=-60
y =30km/hr
x-y=20
x=50km/hr
AArash:
sorry, it should be x+y=80
as we know, total distance= speed *time
Here, total distance is 160km
we take the speed of first car as x km/hr
and the speed of 2nd car be y km/hr
total speed in first case = (x-y) km/hr
total time = 8 hrs
d=st
160=(x-y)*8
which gives
x-y=20 _______(1)
2nd case
total speed = (x+y) km/hr
total time= 2hrs
160 = (x+y)*2
that gives
x+y=80________(2)
subtracting eq 1 from 2
x+y=80
x-y=20
- + -
2y=60
y =30km/hr
x-y=20
x=50km/hr
Here, total distance is 160km
we take the speed of first car as x km/hr
and the speed of 2nd car be y km/hr
total speed in first case = (x-y) km/hr
total time = 8 hrs
d=st
160=(x-y)*8
which gives
x-y=20 _______(1)
2nd case
total speed = (x+y) km/hr
total time= 2hrs
160 = (x+y)*2
that gives
x+y=80________(2)
subtracting eq 1 from 2
x+y=80
x-y=20
- + -
2y=60
y =30km/hr
x-y=20
x=50km/hr
now that's correct
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