ONE MORE QUES. ON PROBABILITY

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.

7 Answers

62
Lokesh Verma ·

11/36 is the answer.

The trick is that |x-y|<10 has to be plotted on a square with origin 0 and length of each side 60 units!

Could u understand the explanation?

1
arjita ·

yes i understood....gud

1
kshatriyan c ·

hi bro !!

please explain the trick !!!

what is the concept ?

62
Lokesh Verma ·

see if u look closely, the idea is to find probability that |x-y|<10/60=1/6 hrs right (their time difference is less than 10 minutes.)

Suppose that the first person comes at time x
and the 2nd person comes at time y

it is also known that 5<x<6 and 5<y<6

plot of x,y will be in a square of size 1.
and their in that square we plot |x-y|<1/6

this will give the favorable area! hence teh solution!
The favorable area will be 1-2.1/2.(5/6)2 = 1 - 25/36
=11/36

62
Lokesh Verma ·

in this image the two lines are the lines between which they can meet.
so the shaded region gives the time they will meet.

x axis is the time when 1st person arrives
y axis is the time when 2nd person arrives.

i hope it is clear now!

1
kshatriyan c ·

hey thank u a lot !!

1
kshatriyan c ·

hey thank u a lot !!

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