Question 32
A library is open every day except Wednesday. One day three boys, $A$, $B$, $C$ visit the library together for the first time. Thereafter they visit the library many times. $A$ always makes his next visit two days after the previous visit, unless the library is closed on that day, in which case he goes the following day. $B$ always makes his next visit three days after the previous visit (or four if the library is closed). $C$ always makes his next visit four days after the previous visit (or five if the library is closed). For example, if $A$ went first on Monday, his next visit would be Thursday, then Saturday. If $B$ went first on Monday, his next visit would be on Thursday. All three boys are subsequently in the library on a Monday. What day of the week was their first visit?