Answer:
He will wear both on the 12th day.
Explanation:
Find the LCM (Least Common Multiple) of 4 and 6.
Prime factor both numbers:
4 = 2²
6 = 2 · 3
LCM = 2² · 3
= 12
To find the LCM, take the greatest common numbers (2² and 3) and multiply them.
This method works well with very big numbers.