probability that it will rain on any given day in the month of April is .02

Hello,

The probability that it will rain on any given day in the month of April is .02. What is the probability that it will rain once in the month of April?

My answer is:
30 * .02 * (.98)^29 = .33397

ssmmss said:

Hello,

The probability that it will rain on any given day in the month of April is .02. What is the probability that it will rain once in the month of April?

My answer is:
30 * .02 * (.98)^29 = .33397

Click to expand...

There is an important bit of information missing!

Are you looking for the probability that it will:

rain only once (and no more) in the month of April

or


rain at least once (and may be more) in the month of April

Subhotosh Khan said:

There is an important bit of information missing!

Are you looking for the probability that it will:

rain only once (and no more) in the month of April

or


rain at least once (and may be more) in the month of April

Click to expand...

Only once. Thanks.

The probability it will rain on any one day is \(\displaystyle .03(.97^29)\) but there are 30 possible days so, yes, the probability it will rain on exactly one day is \(\displaystyle 30(.03)(.97^{29})\).

(The probability that it will rain on at least one day is 1 minus the probability it does not rain at all: \(\displaystyle 1- (.97)^{30}\))