If the mean of a frequency distribution is 100 and the coefficient of variation is 45%, then what is the value of the variance?

Let two events A and B be such that P(A) = L and P(B) = M. Which one of the following is correct?

For which of the following sets of numbers do the mean, median and mode have the same value?

The mean of 12 observations is 75. If two observation are discarded, then the mean of the remaining observations is 65. What is the mean of the discarded observations?