Ecclesiastes 4:12 says a cord of how many strands is not quickly broken?

Answer: Three

After saying "two are better than one," the Teacher adds, "a cord of three strands is not quickly broken" (KJV: "threefold cord").

“And though one may be overpowered, two can resist. Moreover, a cord of three strands is not quickly broken.”— Ecclesiastes 4:12 (BSB)