Final answer:
Marisol and Paul will have to walk for 36 minutes until they are both back at the beginning of the circular path at the same time, which is the Least Common Multiple of their respective walking times.
Step-by-step explanation:
To find out how many minutes Marisol and Paul will have to walk until they are both back at the beginning of the path at the same time, we need to calculate the Least Common Multiple (LCM) of their walking times around the path. Marisol can walk the circular path in 12 minutes, and Paul can do it in 9 minutes.
The multiples of 12 are 12, 24, 36, 48, ..., and the multiples of 9 are 9, 18, 27, 36, ....
The first common multiple of both sets is 36.
Therefore, they will both be back at the starting point together after 36 minutes.