(4) Let the rate of S.I. be r% per annum. ⇒Time = r years S.I. =100Principal×Time×Rate​C.I. = Principal[(1+100RATE​)TIME−1] According to the question, 100Principal×Time×Rate​. = P[(1+100r​)2−1]100r​=10000r​+501​100r​−10000r​=501​ ⇒10000100r−r​=501​ ⇒ 99r =5010000​= 200 r=99200​⇒2992​% per annum