Two different 2-digit numbers are randomly chosen and multiplied together. What is the probability that the resulting product is a multiple of 10?
There are 90 2-digit numbers between 10 and 99 inclusive.
There are: 90 C 2 ==4,005 ways of choosing 2 numbers.
There are 1,089 products that are multiples of 10
Therefore, the probability is: 1,089 / 4,005 ==121 / 445
