Question 883650
Find the greatest number under 100 with those factors, and then add 1.
We can discount 2 and 3 because they multiply to 6.  We know that the number must be even (using 2 as a factor) and must end in 0 (factor of 5 that is even).
6,12,18,24,30,36,42,48,54,60,66,72,78,84,90,96 -- 30,60,90 meet the criteria, all of which are divisible by 5.  What about 4?  90 is not evenly divisible by 4.
30 or 60?
Let's try 60 since we're looking for the greatest number.
60/6=10
60/5=12
60/4=15
60/3=20
60/2=30
Success!
Add 1 for the remainder.  Katie's father is 61.