Bloomberg LP Interview Question
Financial Software DevelopersThe rope does not burn uniformly. This means that rope B calculation may not be appropriate to calculate 15 min.
true! how can you be so sure that ROPE B will be burnt in 15 mins? It is not uniform dude...
no, the solution is correct. accepted that the rope does not burn uniformly in length, but it does burn out in 60 mins. so in 30 mins, rope B would have burnt 30mins worth and would have 30 mins worth length left. so by igniting the other end of B when A has burned out would time the remaining 15mins.
No. The solution is correct. It does not matter whether 1/4 of the rope is burnt in length. We know that exactly 30 minutes of it have burned off. There are 30 minutes of burn time remaining. If we light the other end, it burns twice as fast. Then there are 15 minutes of burn time remaining.
Abe Chutiye,
Its not possible,
See, the rope is not uniform.
It wont burn in 15 minutes accuratesly.
U r doing the question as if the rope is uniform.
here's the correct answer:
1) burn rope A from both the ends and one end of rope B simultaneously ..rope A will burn out in 30 minutes..
2) when rope A burns out , now rope B has 30 more minutes left to burn out.
3)Lit the other end of rope B at that instant...so rope B will take another only 15 minutes instead of 30 to burn out ....therefore 30+15 =45 :) :) :)'
Two ropes A and B
- Thirumalai Thathachary December 15, 2009Ignite both ends of rope A and one end of rope B simultaneously
Rope A will burn out completely in 30 minutes ( refer to reason below if needed ).
Now, at this point ignite the other end of rope B. It will be another
15 mins before the rope B burns out completely. So, it is 30+15=45 mins
for the rope B to completely burn out. thus we can time 45 mins
Reason :
Let L feet be the rope length.
It takes Y mins to burn X feet of the rope, so it takes ( 60 -Y ) mins
to burn the remaining ( L - X ) feet. If you burn both the ends simultaneously,
when the rope burns out, Y=60-Y, so Y has to be 30 mins.
Similarly, it is 15 mins for rope B