Math
posted by bart on .
Assume that the weight loss for the first two months of a diet program has a uniform distrbiution
over the interval 6 to 12 pounds. Find the probability that a person on this diet loses less than 10
pounds in the first two months.
Not sure what to do.
A) 1/6
B) 5/7
C) 1/3
D) 2/3

The answer is 2/3.
[106]/[126] = 4/6 =2/3 
From your data, there is possibility of losing 6, 7, 8, 9, 10, 11, or 12 pounds. "Less than 10 pounds" includes 6, 7, 8 and 9 pounds lost.
I get 4/7. However,if you say ≤ 10, then it would be 5/7. 
I do not know what to do. I used the Venn diagram for myself but I think I was wrong as I got 4/7 as PsyDag did. I don't think 5/7 is correct as the problem doesn't say equal to or less than 10. I do not understand Adam's equation and solution. Could you please help me understand?