ProbabilityHard
Question
Two distinct numbers a and b are selected at random from $1,2,3,\ldots\ldots,50$. The probability, that their product ab is divisible by 3 , is
Options
A.$\frac{561}{1225}$
B.$\frac{664}{1225}$
C.$\frac{272}{1225}$
D.$\frac{8}{25}$
Solution
Req. probability $= 1$ - (product not divisible by 3 )
Multiple of $3 = 16$
Not multiple of $3 = 34$
$$= 1 - \frac{\ ^{34}C_{2}}{\ ^{50}C_{2}} = \frac{664}{1225}$$
Create a free account to view solution
View Solution FreeMore Probability Questions
A number is chosen at random from the numbers 10 to 99. By seeing the number a man will laugh if product of digits is 12...Two integers are selected from integers 1 to 11. If their sum is even then the probability that both are odd will be-...Three houses are available in a locality. Three persons apply for the houses. Each applies for one house without consult...Seven white balls and three black balls are randomly placed in a row. The probability that no two black balls are placed...Let p be the probability that a man aged x years will die in a year time. The probability that out of ′n′ me...