Question

A six sided die is tossed. What is the probability that it shows a prime number if you know the following?

a. It shows an even number.
b. It shows a number less than 5.
c. It does not show a 6.
d. It shows 1 or 2/
e. It shows an even number less than 4.
f. It shows a number greater than 3.

Answer 1

a) the only even prime is the number 2 so
prob = 1/6

b) primes less than 5 are : 2 and 3
so prob = 2/6 = 1/3

c) if not a 6, then it must be: 1, 2, 3, 4, or 5
how many of those are prime?

d) which of 1 or 2 is prime ?

e) how many even's < 4 are prime?

etc.