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2015 CIMC keystage3-IWYMIC individual Question 14

xIMC · 2015 CIMC keystage3-IWYMIC individual

Question 14

A number consists of three distinct digits chosen at random from $1,2,3,4,5,6,7,8$ and $9$ and then arranged in descending order. A second number is constructed in the same way except that the digit $9$ may not be used. What is the probability that the first number is strictly greater than the second number?