Question

What is the probability of rolling a 3 on a six-sided cube AND rolling a 6 on a six-sided cube?

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Answer 1

16.7%

Explanation:

There are 6 sides and one three on the cube so rolling a three would be 1/6. To roll a 6 on a 6 sized dice would be the same there’s 6 sides and one 6 so it would be 1/6

Answer 2

The probability of not rolling a 5 AND not spinning a 5 is (5/6)*(4/5)=20/30

Explanation:

These are independent events.

The probability of rolling a 5 is 1/6.

The probability of spinning a 5 is 1/5.

The probability of rolling a 5 or spinning a 5 is 1/5+1/6=11/30 but you have to subtract 1/30 because you can roll a 5 and spin a 5 at the same time. Therefore 11/30-1/30=10/30=1/3.

There are 30 outcomes. Roll first then spin to get the following outcomes:

11,12,13,14,15,21,22,23,24,25,31,32,33,34,35,41,42,43,44,45,51,52,53,54,55,61,62,63,64,65

You want to roll a 5 OR spin a 5. How many combinations have a 5 ? 10 combinations have a 5.

(you don't count 55 twice) There are 10 combinations with a 5 out of a possible 30 combinations.

Another way of looking at the problem is the following:What is the probability of NOT rolling a 5 AND NOT spinning a 5 ?

The probability of not rolling a 5 AND not spinning a 5 is (5/6)*(4/5)=20/30. Therefore the probability of rolling a 5 or spinning a 5 is 1-20/30=10/30.