Question

A prime die uses the first six prime numbers on its faces, one prime per face. When two prime dice are rolled randomly, there is a 1/36 probability that the product of the two numbers will be equal to 4. What is the probability that the product has a units digit of one

Answer 1

Answer:
`(5)/(36)`

Explanation:

Given

dice with Prime number is rolled

The number on the face of dice are 2,3,5,7,11 and 13

Probability of getting a product of 4 is
`(1)/(36)`

Now probability of getting product has a unit digit one is possible when outcome is

`(3,7),(7,3),(13,7),(7,13),(11,11)`

i.e. there are 5 favorable outcomes

So probability is
`(5)/(36)`