# Find out how unlikely Y is than X — when X is 50% more likely to cure cancer than Y [closed]

So 50% likely to me sounds like 150% percent that X will cure cancer, and 100% that Y will cure cancer. Other than this, I have NO IDEA without googling how to figure this out. Detailed explanation is good.

edit: 66% unlikely (or likely???) that Y will cure cancer when compared to X --

now What are the basic rules that is needed to figure this out, along with other similar problems?

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I don't understand this! If Y will cure cancer for 2% of patients (in some relevant group), then with your assumptions X will cure 3% oy your patients. I have no idea where younget those 150% from, and neither what it could mean. You should try to reformulate! –  kjetil b halvorsen Sep 25 '12 at 22:43
2/3 = 66% | 100/150 = 66% | y/x=ANSWER || was that too hard to answer? –  kittensatplay Sep 26 '12 at 4:48
About your request to migrate to math.se, Math moderators and I agree that this question can stay on Cross Validated. However, I would like to remind you that respectful and constructive comments are more likely to attract good answers and generate fruitful exchanges on SE sites. –  chl Sep 26 '12 at 8:51
It is hard to make sense of the (ungrammatical) phrase "find out how unlikely Y is than X," which leaves many readers guessing what this question might mean. Could you please clarify it? –  whuber Sep 26 '12 at 12:56
@kittensatplay, after reviewing several of your contributions to the site, I think you may benefit from reading the first few sections of the FAQ, which address accepted practices on how to ask questions. You may also want to look at section on etiquette. –  Macro Oct 7 '12 at 23:54

## closed as not a real question by rolando2, gung, Andy W, Peter Flom♦, MacroSep 29 '12 at 7:10

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

Call the probability that Y cures cancer $a$. Since X is 50% more likely to cure cancer, its probability of curing cancer is $b = 1.5 \times a$.

If you do not know the probability that X cures cancer you are stuck. If you know that it is 0.15 (say) then $a$ is 0.10.

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so ur saying there isnt an inverse to finding out "how unlikely Y is than X" given "X is 50% more likely" ....so ur telling me that when these garbage sites tell me that "X is P% more likely to Z than Y" -- it is completely useless and meaningless because the whole of these people dont know any math... because few teachers can teach us math properly. ok –  kittensatplay Sep 26 '12 at 4:43
If $a=80$%, say, do you want the reader to conclude that $1.5\times 80$% = $120$% is a probability? Really? –  whuber Sep 26 '12 at 12:52