Question

Henry rolls 2 number cubes numbered 1 through 6 while playing his favorite board game. He will get a second turn if he rolls a sum that is an even number less than 10.
What are Henry's chances of getting a second turn when he rolls the number cubes?

7/18
11/18
5/36
17/36

I got 5/18. I added up the amount of different ways to get 2-8. I found 10. Either the test is wrong or I'm really bad at counting, and I'm not confident enough to count either of them out.

Answer 1

only less than? not 'less than or equal to' ?

Answer 2

The sample space has 36 possible combinations of numbers. These can be set out in column form as follows:
6,6 5,6 4,6 3,6 2,6 1,6
6,5 5,5 4,5 3,5 2,5 1,5
6,4 5,4 4,4 3,4 2,4 1,4
6,3 5,3 4,3 3,3 2,3 1,3
6,2 5,2 4,2 3,2 2,2 1,2
6,1 5,1 4,1 3,1 2,1 1,1

I get 1 in the first row, 2 in the second row, 2 in the third row, 3 in the fourth row, 3in the fifth row and 3 in the sixth row.

Answer 3

That makes 14 pairs out of 36 possible pairings.

Answer 4

I don't know if the count duplicates, like 4+2 and 2+4. I didn't.

Answer 5

*they

Answer 6

Yes, 4+2 and 2 + 4 are counted. Strictly they are not duplicates, the reason being the order is reversed.

Answer 7

Okay. Thank you! I've taken a test twice now (this is my last chance), and both times I got this type of question wrong. Thank you for your help!

Answer 8

It was correct! Thank you again!

Answer 9

You're welcome :)
Hint: Remember to simplify the fraction.