Randomly place +" or -" into the following boxes,
◻ 1/2 ◻ 1/3 ◻ 1/4 ◻ 1/15
What is the probability that the result is positive but no greater than 1/20?
Getting a common denominator we have
30/60 20/60 15/60 4/60
We need the result to be < 3/60 (but positive)
We have 8 possibilities
+ + + reject as too large
+ + - reject as too large
+ - - reject as too large
- - - reject (negative result)
- - + reject (negative result)
- + + reject as too large
+ - + reject as too large
- + - reject as too large
The probability is 0