Pinned Eric Adjei Cape Coast, Ghana 141 Questions 74 Answers 14 Best Answers 965 Points View Profile 5 Poll Eric AdjeiAssociate Professor Asked: January 1, 20212021-01-01T22:56:39+00:00 2021-01-01T22:56:39+00:00In: how How long is a decade? 5 Poll Results 0%A decade is 5 years. 100%A decade is 10 years. ( 3 voters ) 0%A decade is 15 years. Based On 3 Votes Participate in Poll, Choose Your Answer. A decade is 5 years. A decade is 10 years. A decade is 15 years. How long is a decade? how long is a decade Share Facebook Leave an answerCancel replyYou must login to can add an answer. Username or email* Password* Remember Me! Forgot Password?