Posted by Paul on .
I am a two digit number greater than 40.You can divide me by 7 and also by 8, but not any other set of single digit number.what number am I

Math riddle 
Ms. Sue,
Multiples of 7:
49, 56, 63, 70, 77, 84, 91, 98
Multiples of 8:
48, 56, 64, 72, 80, 88, 96
Which of those numbers answer your question? 
Math riddle 
MathMate,
At first sight, the answer is the LCM (Lowest common multiple) of 7 and 8?
Looking further, there is a problem with the question ("but not any other set of single digit number"). Any number divisible by 8 is also divisible by 2 and 4, hence the twodigit number divisible by 7 and 8 will always be divisible by 7, 8, 4 and 2. 
Math riddle 
Paul,
Thanks, Ms. Sue
Mathmate thanks that's what I thought just wanted to make sure maybe it was a misprint on the riddle. 
Math riddle 
Ms. Sue,
I read the problem as the PAIR of numbers that can go into the two digit numbers. The numbers 7 and 8 are the only single digit PAIR of numbers that fit that description.

Math riddle 
MathMate,
Ms Sue, I think your interpretation is very reasonable.
However, mathematically speaking, there is no limit on the number of members in a set. As Paul indicated, there is probably a misprint, where it read "but not any other SET of single digit numbers" it is probably supposed to read "but not any other PAIR of single digit numbers". 
Math riddle 
Ms. Sue,
Thanks, MathMate.