WBCS Exam Main Compulsory Question Paper VI - 2015 [ Arithmetic and Test of Reasoning ]

1. Five bells tolled together and since then they began to toll at intervals $3{1 \over 3}$, $2{2 \over 5}$, $2{2 \over 7}$, $2{2 \over 9}$ and $2{1 \over 2}$ secs. They will again toll together after (A) 3 minutes (B) 4 minutes (C) 5 minutes (D) 6 minutes