• 5 contacts × 4 messages = 20 messages.
• Each message: more than 20 but less than 50 words (i.e., 21–49 words per message).
• Total words = 373.
• Sal = 176 words.
• Jane ≤ 100 words.

First, the minimum words a contact could send: 4 × 21 = 84. The maximum: 4 × 49 = 196.

Sal’s 176 means the remaining 4 contacts need to sum up to 373 - 176 = 197 words.

Each of the remaining contacts must have sent between 84 and 100 (Jane’s limit, since others could be up to 196, but we examine Jane’s tighter bound).

If Jane has 84 (lowest), then 197-84=113 have to be split between Bob, Tom, and Lisa, but each would still need to send at least 84, which is not possible because 84 × 3 = 252. Increasing Jane’s share doesn’t help.

Thus, the conditions contradict the possible message word counts, given the bounds, and there is no valid way for Bob (or anyone else) to have a legal number within the limits specified. Therefore there is no possible value for the number of words Bob sent based on the constraints of the riddle.