The largest term common to the sequences 1, 11, 21, 31…….. to 100 terms and 31, 36, 41, 46……. to 100 terms is

100th  term 1, 11, 21, 31, ….. is 1+ (100 -1) 10 = 991.100th term of 31, 36, 41, 46…. Is 31+ (100-1) 5 = 526.Let the largest common term be 526. Then,526 = 31+(n-1) 10  ⇒n=50.5But n is an integer, hence n=50. Hence , the largest common term is 31+50−110=521