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You roll 2 six-sided dice. Find the probability the sum is less than 8. SHOW/EXPLAIN YOUR WORK

User Thund
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1 Answer

6 votes

Answer:

7/12

Explanation:

You can do some casework to find the answer here. There are a total of 36 possible outcomes when you roll two dice, since each die has 6 options.

Rolling a sum of 2:

There is only one way for this to happen; if both dice land on a 1. Therefore, there is only one outcome where this happens.

Rolling a sum of 3:

There are two ways for this to happen; 1-2 and 2-1.

Rolling a sum of 4:

1-3, 2-2, 3-3. Total of 3 ways.

Rolling a sum of 5:

1-4, 2-3, 3-2, 4-1. Total of 4 ways.

Rolling a sum of 6:

1-5, 2-4, 3-3, 4-2, 5-1. Total of 5 ways.

Rolling a sum of 7:

1-6, 2-5, 3-4, 4-3, 5-2, 6-1. Total of 6 ways.

1+2+3+4+5+6=21 total outcomes where the sum of the dice rolls is less than 8. Therefore, the probability of this happening is 21/36=7/12. Hope this helps!

User Ben Ylvisaker
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