Charlton syndrome is a new found syndrome. It is when somebody tends to write random natural numbers smaller than 100 down for no reason. If 5 people suffer from Charlton syndrome, what is the probability that no two people would write the same number? The answer can be expressed as a/b where a and b are co-prime integers. Find the digit sum of (a+b).
Details and assumptions
They each write only one number
I could be wrong