RSS
Proportion Of Ones
Problem
If we consider 2-digit numbers, there are exactly 18 numbers that contain the digit one:
10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
21, 31, 41, 51, 61, 71, 81, 91
As there are ninety 2-digit numbers, the probability of a 2-digit number containing a one is 18/90 = 1/5.
What proportion of 3-digit numbers contain the digit one?
Problem ID: 189 (28 Nov 2004) Difficulty: 2 Star
Show Solution
Hide Solution