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A and B run in opposite directions from a pt. P on a circle with different but constant speeds. A runs in clockwise direction. They meet for the first time at a distance of 900 m in clockwise direction from P and for the second time at a distance of 800 m in anticlockwise direction from P. If B is yet to complete one round, the circumference of the circle is
a) 1700m b) 1250m c) 1300m d) 1200m
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- 1300 answer
- 9 years agoHelpfull: Yes(0) No(0)
- How?
exaplain - 9 years agoHelpfull: Yes(0) No(0)
- p is the perimeter of the circle
Suppose after t1 time they first met and a is the speed of A and b is the speed of B
a*t1=900
b*t1=-p+900 {p is minus for anti clock wise direction}
Suppose after time t2 they again met
b*t2=-800
a*t2= p+p -800 {extra p because the A is on its second round}
so from first set of equation
we have
a/b=900/(-p+900)
and from second set we have
a/b= (2p-800)/-800
so from these two equation compare their R.H.S
we have (2p-800)/-800 = 900/(-p+900)
cross multiply
then we have
-2psquare + 1800 p +800p = 0
simplify the equation we have
psquare - 1300p=0
finally we have p= 1300
- 9 years agoHelpfull: Yes(0) No(0)
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