Consider the following problem:
Two people $M$ and $T$ walk over a straight line. The steps they take depend on flipping a coin: They move to the left if the result is head and they move to the right if the result is tail. Person $M$ stops after two consecutive steps to the left. Person $T$ stops after one steps to the left and inmediatly after one step to the right. Find the expected value of steps each person takes before stoping.
I honestly have know idea how to begin solving the exercise. Any help is more than welcome.