Answer:
12 weeks
Explanation:
We know that Salvatore attends class every 4 week, chess club every 2 weeks, and fencing lessons every 3 weeks.
If he attended all today, to find out when he will attend all again,we just need to find the least common multiple (LCM) of 3, 4, and 2.
The LCM of 3, 4, and 2 is 12.
So, he will attend all classes again after 12 weeks.