A mathematician walking leisurely down a street on a Sunday afternoon spotted a colleague he had not seen for some time.
“Hello Fred, nice to see you.
“Likewise, Leonard, I see you are well,” replied Fred, shaking his hand. “Did you ever marry Helen?”
“Yes, I did and now we have three children,” replied Leonard.
“Glad to hear it. How old are your children,” asked Fred.
“As you are a colleague, I will give you the answer in a mental package,” smiled Leonard.
“Ok, hand it over,” said Fred.
“Well, the sum of their ages is a perfect number. Twenty-one times Sarah’s age is the ninth heptagonal number. The product of their ages is a number whose double cross sum is nine. Jason is five years younger than Alex. Is that sufficient information for you,” chuckled Leonard.
“More than sufficient,” replied Fred and promptly gave Leonard their correct ages.
“Next time I see you, I will also set you a small task,” laughed Fred and invited Leonard to come along to his favorite inn to discuss old times.