a car is parked by an owner amongst 25 cars in a row, not at two extremes.on his return, he finds that exactly 15 places are still occupied.the probability that both neighbouring places are vacant is:
I always like to walk in rain as no one can see me crying there :(
frnds are like diamonds , if u hit them , they don't break but they slip frm ur hands
-----It is better to be hated for what you are than to be loved for what you are not.----
*****wen love and skill work together--expect a masterpiece*****
Well forfinding his car , total number of ways = N-1CR-1 ?.(as 1 car is his own , we wont count it)
Where N = 25 (total number of cars standing)
R = no. of places still occupied = 15
So total no. of cases = 24C14
As neighbouring slots are empty , the 14 cars (excluding his car) must be parked in 21 places?..
Number of favourable cases = 21C14
So probability = 21C14/24C14 = 15/253
dats my method dude
I always like to walk in rain as no one can see me crying there :(
frnds are like diamonds , if u hit them , they don't break but they slip frm ur hands
-----It is better to be hated for what you are than to be loved for what you are not.----
*****wen love and skill work together--expect a masterpiece*****
in case of favourable cases..then u have considered that there will be 14 cars in 21 places...but it has to be 22 places because one of his own,and the adjacent places..so its 25-3=22
I always like to walk in rain as no one can see me crying there :(
frnds are like diamonds , if u hit them , they don't break but they slip frm ur hands
-----It is better to be hated for what you are than to be loved for what you are not.----
*****wen love and skill work together--expect a masterpiece*****
Moderation Team
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