A and b stand at distinct points of a circular race track of length 135 m. they cycle at a speed of a m/s and b m/s. they meet for the 1st time 9sec. after they start the race and for the second time 24 sec from the time they start the race. now if b had started in the opposite direction to the one he had originally started. they would have met for the first time after the 18sec. if b is quicker then a , then find b?
Answers
Answer:
b = 6 m/sec
Step-by-step explanation:
A and b stand at distinct points of a circular race track of length 135 m. they cycle at a speed of a m/s and b m/s. they meet for the 1st time 9sec. after they start the race and for the second time 24 sec from the time they start the race. now if b had started in the opposite direction to the one he had originally started. they would have met for the first time after the 18sec. if b is quicker then a , then find b?
After meeting together they meet again in 24-9 = 15 sec
so with in 15 sec they completed on e lap together
one lap = 135 m
a + b = 135/15
=> a + b = 9 m/s - eq 1
first time they meet after 9 sec
so ditance covered by both = (9) * 9 = 81m
Distance between them was 81m in that direction
in other direction distance was 135 - 81 = 54 m
Now if b had started in opposite direction so to meet a
he has to cover the distance covered by a + 54m
b*18 = a18 + 54
=> (b-a)18 = 54
=> b-a = 3 - eq 2
Adding eq 1 + eq 2
2b = 12 m/s
=> b = 6 m/sec