Question

You roll 2 dice. What is the probability that the sum of the dice is even and 1 die shows a 3?

Answer 1

probability that one die shows a 3 = (1/6)
now for the sum to be even the other die must show one of which values

Answer 2

hmm... 1, 3, 5?

Answer 3

exactly
so whats probability of 1,3 or 5?

Answer 4

1/2

Answer 5

right
now the two events ( the 3 and 1,3,5) are independent so the 2 probabilities are multiplied

1/2 * 1/6

Answer 6

1/12

Answer 7

is it 1/12 then?

Answer 8

????

Answer 9

wow it's wrong... it's 5/36

Answer 10

hmm - lets look at it again

Answer 11

i've missed something here - yes the 3 can be on either dice -
well if the 3 is on the other dice instead that doubles the probability - giving 1/6
- thats still wrong

Answer 12

- oh 2 '3' isn't two events - just one - so that subtracts 1/36 from 1/6
giving 5/36

-this was more complicated than it appears

sorry guy - but we got there in the end

Answer 13

do you follow?

all possibilities are

3 and 1
3 and 5
1 and 3
5 and 3
3 and 3

probabilities for each is 1/36

total probabilities = 5/36

- that way was a lot easier!!!

Answer 14

lol