QOD #12
Riki doesn't want to be in a QOD. He tried all he can to get me to make it about someone else. He dropped hints that a certain Chris O'Donnell-looking student seemed to be interested in a tennis camper. He walked around threateningly with a broomstick, and he even begged me to make a QOD about a certain SSP'er and her mop-haired-alum-admirer. Of course, this only made him a more likely target. But it became a necessity when I heard him talking to Peter.
"Peter, you think you are so smart! But I can tell whether a number is divisible by 3!"
"I don't give a HOOT," Peter exclaimed, wide eyed, "You just add the digits and if the sum is divisible by three, then so is the number."
Riki was clearly distressed by this, and needed a quick comeback. "Well, actually, I know a simple way to tell if a number is divisible by 7, 11, 13, even 37, without dividing it."
"Wow." Peter said, flabbergasted, and his head spun 180 degrees and he pounced aon a small mouse. "What is it?"
"Uhh," Riki stuttered, "I'll tell you after dinner."
Can you help Riki find out a method of determing whether a number is divisible by those primes, before he embarrasses himself in front of Peter? You get points for each prime you figure out.
Solution and comments
