383i think 16
2 frnds after a long time decided to meet at a particular coffee shop between 5:00 pm to 6:00 pm on a specified day.they also decided that the person whho comes earlier will not wait for the second person for more than 10mins. find the probability that they meet.
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13 Answers
1708I am Getting probability = 2536
Dwijaraj Paul Chowdhury How?
Upvote·0· Reply ·2013-02-28 06:56:10
1057do this one using graph
make a 60x60 square starting from origin....60 because the total time span is 60 min.......
plot |x-y|≤10
find the ratio of that area to the area of the square..
answer will come 11/36.
- Soumyabrata Mondal why you r plotting (|x-y|≤10) this graph???
- Ketan Chandak because arrival time difference should be less than 10 mins....only then will they meet...
1057@akshay....we are doing serious work here... :P
Swarna Kamal Dhyawala ya its 61 mins 5:00pm to 6:00pm .even 6:00pm is included
36If friends are a and b. Both friends will reach at some time in the span.
Let a be the one who reaches first. (this is vital)
Now, if he reaches in the first 10 min span, probability of meeting friend is 1/6
if he reaches in the second span, prob of meeting b is 1/5
...... if he reaches in 6th span, probability of meeting friend is 1/1 (as b has to reach after him)
It doesnt really matter if a reaches first or b.
so total prob. is {(1/6)+(1/5)+.....(1/1)}/6
=147/360
36If a reaches first
If he reaches in the first minute, probability of meeting is10/60
If he reaches in the second minute it is 10/59
If in the 50 th minute, 10/11
If in the 51st minute, 1
If in the 52nd minute, 1
So total probability is (10/60+10/59.....10/11)+(1+1+....10 times)whole by 60
