Two letters are chosen at random *with replacement *from the word PROBABILITY. Note there are 11 letters in total in PROBABILITY.

a) P and T each only occur once in the word. The probability of choosing P and T in a particular order (eg P then T) is

Pr(PT) = Pr(P) x Pr(T) (as they are *independent *events)

= (1/11) x (1/11) = 1/121

There are only two orders the letters can be in: PT or TP, so the probability of P and T in any order is

Pr(PT) + Pr(TP) = 1/121 + 1/121 = 2/121

b) The probability of choosing 2 B's is

(2/11) x (2/11) = 4/121

There is only one order for choosing...

(The entire section contains 312 words.)

## Unlock This Answer Now

Start your **48-hour free trial** to unlock this answer and thousands more. Enjoy eNotes ad-free and cancel anytime.

Already a member? Log in here.