Elitmus
Exam
Logical Reasoning
Cryptography
There is a circular track of length 440m. There are 3 persons A, B and C standing at different points on the track ready to start the race.A an B are standing diametrically opposite to each other while C is exactly midway between A an B, such that A, B and C are standing in clockwise order. The race started at 10 am. The speeds of A,B and C are respectively 5m/s,10m/s and 8m/s. at what time would B and C meet for the second time,if all the three of them run in the clockwise direction.
option
a) 10:06:25 am
b) 10:04:35 am
c) 10:00:50 am
d) none of these.
Read Solution (Total 12)
-
- answer is (B)
speed of B is 10m/s, speed of C is 8m/s.
speed of B with respect to C in clockwise direction is 2m/s.
B is 110m behind C in clockwise direction.
Hence to pass C twice, B will travel 110+440=550m clockwise with the relative speed of 2m/s.
time taken by B to do so is (550/2)=275sec or 4min35sec.
- 11 years agoHelpfull: Yes(39) No(4)
- answer is B
distance between b and c is 110m, relative speed of b over c= 2m/s
1st meet after t1=110/2=55sec
2nd meet after LCM (Time taken by C in one round, same for B)
LCM(55,44)=220sec
total time = 220+55=275 sec (4 minute 35 sec) - 11 years agoHelpfull: Yes(6) No(2)
- when v r considering relative vel. how the person with smaller vel vl move 4ward??the solution vl b---The relative speed between Harb and Inz: 10 - 8 = 2 m/s and they are 330m apart
Therefore, 330/2 = 165 sec; 2 min 45 sec; when they meet the 1st time it will be 10:02:45
When they meet the 2nd time: 440/2 = 220 sec; 3 min 40 sec
10:02:45
+ 03:40
--------------
10:06:25 when they meet the 2nd time - 10 years agoHelpfull: Yes(4) No(4)
- The relative speed between Harb and Inz: 10 - 8 = 2 m/s and they are 330m apart
Therefore, 330/2 = 165 sec; 2 min 45 sec; when they meet the 1st time it will be 10:02:45
When they meet the 2nd time: 440/2 = 220 sec; 3 min 40 sec
10:02:45
+ 03:40
--------------
10:06:25 when they meet the 2nd time - 10 years agoHelpfull: Yes(3) No(5)
- ans a) 10:06:25 am...explanation...
relative speed of A and B 10-8 = 2 m/s
for the second meeting of A and B distance to be covered is 330+440=770 m
time to cover this distance 770/2 =385 sec = 77/12 min= 6 min 25 sec... - 11 years agoHelpfull: Yes(2) No(10)
- oops ...there should be B and C in place of A and B in above solution...
- 11 years agoHelpfull: Yes(1) No(6)
- ans is A but
first meet = 330/2= 165s
second meet after completing one round bcoz clock waise movement and speed is difer. so after 1 round difference b/w them is 440-88. now cover this distance by a is in the tyme 352/2= 176. 44s taken by B to i round = 176+44=220.
total tym= 220+165= 375/60= 6:25s. - 10 years agoHelpfull: Yes(1) No(3)
- after meeting for the first time B and C will be at the same point and start from there but since B has higher speed and c has lower so C will always follow B but can not cross him.
- 11 years agoHelpfull: Yes(0) No(1)
- i think it's depends on the standing position of A and B if clockwise sequence is BCA then option b if ACB then option a
- 11 years agoHelpfull: Yes(0) No(1)
- i think correct ans is D:
distance between b and c = 110
relative speed b/w b,c = 10-8 =2
first time they meet after 110/2= 55 sec
and they again(2 time) meet {LCM of 10 ,8 is 40} ;
so b and c always meet after 40sec +55
total time 95 sec.mean they meet 10:01:35 - 11 years agoHelpfull: Yes(0) No(3)
- can any one make me understand that in all the solution how value of 'z' and 'w' became 9..:(.. its quite confusing
- 8 years agoHelpfull: Yes(0) No(0)
- answer is d) none of these
B and C meet for the first time at 10:03:36 am
for the second time they meet at 10:07:18 am
calculate yourself - 5 years agoHelpfull: Yes(0) No(0)
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