Submitted by Anonymous (not verified) on
Forums:
After completing question 12, I checked the answers, and in the latter part of 12b, the model solution uses x=0.6-k. I am unsure of what k represents. It looked as if it represented the probability of wearing either a hat only or a hat and a ring only, but I don't think that was consistent with the remainder of the model solution. Any ideas?
Which answers?
Submitted by cxm on
Which model answer did you check? There are various sources out there some better than others. If we let x = P(wears H and C but not R), y=P(H and R but not C) and z = P(R and C but not H). You can then draw a venn diagram.
You can then find expressions for thing like P(Hat only) = 0.7 - 0.1 - x - y = 0.6 - x- y (which might be the 0.6 - k?). There will be three of these.
You can also use the total area:
0.05+0.1+x+y+z+(0.6 - x - y)+ ... = 1
And use this to find x+y+z which is the probability you want.