Seattle Mariners First-Place Elimination Scenario
Seattle must win 5 more games (69 total) to avoid elimination from first place.
Here are the final standings in a scenario in which Seattle finishes in first place with 69 wins:

Team             W	L	PCT	GB
Seattle          69	93	0.426	0.00
Houston          69	93	0.426	0.00
LAAngels         68	94	0.420	1.00
Texas            68	94	0.420	1.00
Oakland          67	95	0.414	2.00

Tie breakers
Seattle wins the series with Houston 11 games to 2

To construct the scenario, we start with the current standings in the division:
Team             W	L	GL	PCT	GB
Houston          69	68	25	0.504	0.0
Texas            67	70	25	0.489	2.0
Seattle          64	73	25	0.467	5.0
Oakland          53	84	25	0.387	16.0
LAAngels         52	85	25	0.380	17.0

Next, we show how the remaining series of games plays out in the scenario:

Houston currently has 7 win(s) against LAAngels and 6 loss(es).
Houston and LAAngels have no remaining games.
Houston wins the series 7 games to 6.
Houston wins 0 additional game(s) against teams outside the division and loses 19.

Houston currently has 4 win(s) against Oakland and 5 loss(es).
Houston wins 0 additional game(s) against Oakland and loses 4.
Houston loses the series 4 games to 9.
Houston wins 0 additional game(s) against teams outside the division and loses 19.

Houston currently has 2 win(s) against Seattle and 9 loss(es).
Houston wins 0 additional game(s) against Seattle and loses 2.
Houston loses the series 2 games to 11.
Houston wins 0 additional game(s) against teams outside the division and loses 19.

Houston currently has 9 win(s) against Texas and 4 loss(es).
Houston and Texas have no remaining games.
Houston wins the series 9 games to 4.
Houston wins 0 additional game(s) against teams outside the division and loses 19.

LAAngels currently has 5 win(s) against Oakland and 6 loss(es).
LAAngels wins 2 additional game(s) against Oakland and loses 0.
LAAngels wins the series 7 games to 6.
LAAngels wins 7 additional game(s) against teams outside the division and loses 9.

LAAngels currently has 2 win(s) against Seattle and 4 loss(es).
LAAngels wins 7 additional game(s) against Seattle and loses 0.
LAAngels wins the series 9 games to 4.
LAAngels wins 7 additional game(s) against teams outside the division and loses 9.

LAAngels currently has 8 win(s) against Texas and 5 loss(es).
LAAngels and Texas have no remaining games.
LAAngels wins the series 8 games to 5.
LAAngels wins 7 additional game(s) against teams outside the division and loses 9.

Oakland currently has 2 win(s) against Seattle and 4 loss(es).
Oakland wins 7 additional game(s) against Seattle and loses 0.
Oakland wins the series 9 games to 4.
Oakland wins 0 additional game(s) against teams outside the division and loses 9.

Oakland currently has 6 win(s) against Texas and 4 loss(es).
Oakland wins 3 additional game(s) against Texas and loses 0.
Oakland wins the series 9 games to 4.
Oakland wins 0 additional game(s) against teams outside the division and loses 9.

Seattle currently has 3 win(s) against Texas and 7 loss(es).
Seattle wins 3 additional game(s) against Texas and loses 0.
Seattle loses the series 6 games to 7.
Seattle wins 0 additional game(s) against teams outside the division and loses 6.

# Seattle Mariners' magic number
# Seattle's magic number
# Mariners' magic number
# MLB Playoff Race