Your friends bike together, leaving your house and heading North. Once they reach the fork in the road, three will head to the left while the other three head to the right. Then, when each group arrives at a house, the resident of that house leaves the group and heads home.

Tina must have been the only person with your missing friend when they split ways. So, Tina either lives in the middle house or the last house on her street. 

For this puzzle, you’re only trying to find which friend is missing. You won’t be able to locate all of your friends’ houses, but you can figure out who’s missing.

Both Tina and Rosa live  on the even side of the street, with either Walt or Ryan living in the other house. 

Try your friend’s name in the combination lock.

You can deduce the following information from the logic clues:

-Since Tina was the last person to see your friend, she lives in the middle or last house on the street.

-Since Mary and Tina live in the same color houses, they both live in the green houses (1 and 6).

-Thus, Tina lives in house 6, and Mary lives in house 1. That means your missing friend lives in house 4.

-Two girls live on the even side of the street. We know Mary lives in house 1, so both Tina and Rosa must live on the even side of the street.

-Also either Walt or Ryan lives on the even side of the street, so we know that Tina, Rosa, and Walt or Ryan lives on the same street.

-Rosa is alphabetically before Tina, Walt, and Ryan, so she must be your missing friend.

The lock opens with the word Rosa.