Thread: HArd problem?

A. Only once in American history has there been a decade (1790’s, 1940’s, etc.) in which four of the years (as four-digit numbers) were prime numbers. Find it.

B. Find the first decade (A.D.) in which all of the years were composite (non-prime) numbers. (Hint: America was not around then.)

Hey thanks for helping me out. your help is greatly appresciated!!!!!!!

Originally Posted by anime_mania

A. Only once in American history has there been a decade (1790’s, 1940’s, etc.) in which four of the years (as four-digit numbers) were prime numbers. Find it.

I assume you want 1777 but 1 is not prime. There is no answer.

B. Find the first decade (A.D.) in which all of the years were composite (non-prime) numbers. (Hint: America was not around then.)

1 A.D.