perplexus.info :: Probability : Probing the prob.

Probing the prob. (Posted on 2014-01-21)

Chose at random two distinct decimal digits.
Denote them as A & B.

1. What is the probability that:AB is less than A+B?
2. Same question, but with the word "distinct" erased.

See The Solution Submitted by Ady TZIDON

Rating: 3.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

2nd question first (spoiler)

| Comment 1 of 5

AB < (A + B) if A or B is 0 or 1, unless they are both 0.

Part 2)

Probability, if A and B can be the same =

This is 35 ways out of 100 = .35

Part 1)

Probability, if A and B are distinct =

34 ways out of 90 = .377..

I haven't checked this result, so I might need to be corrected

Posted by Steve Herman on 2014-01-21 10:25:18

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