Students of a class were given an aptitude test. Marks were found to be normally distributed with mean 60 and S.D. 5. Find the percentage of students who scored more than 60 marks.

In a packet of 50 pens, 10 are defective, 10 pens are selected at random. What is the probability that atleast one is defective.

The random variable X has the normal distribution f(x) = \(C{ e }^{ -\left( \frac { x-100 }{ 50 } \right) ^{ 2 } }\), then find the value of C.

If you buy a lottery ticket in 50 lotteries, in each which your chance of winning a prize is \(\frac { 1 }{ 100 } \). What is the approximate probability that you will win a prize at least once (e-0.5 = 0.6066). 

The probability of the happening of an event X is 0.002 in an experiment. If an experiment is reported 1000 times, find the probability that the event X happens exactly twice? (e^-2 = 0.1353)