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- Mon Jan 20, 2014 12:00 am
#47068
Setup and Rule Diagram Explanation
This is an Advanced Linear: Balanced game.
The game scenario and first two rules create an Advanced Linear scenario:
The third rule helpfully assigns females to two of the eight wings:
The fourth rule indicates that if males are assigned to a wing, the other wing must be assigned females. Operationally, this means that males can never be assigned to both wings of a dormitory, which results in a vertical not-block:
The fifth rule is conditional:
Of course, if the fifth rule is enacted, and both those wings are assigned males, then by applying the fourth rule, the other wings in those dormitories would be assigned females:
Thus, if Veblen South is assigned males, the Veblen and Wisteria dormitories are fully assigned.
This game also contains a two-value system: each dormitory is assigned either male or female students. Thus, if a dormitory does not have male students, then the dormitory must have female students. As is so often the case, the two-value system can be applied to a conditional rule to create greater insight. Consider the contrapositive of the final rule:
The same contrapositive reinterpreted by applying the two-value system:
This inference is directly tested in question #3.
Another point of restriction in the game is the males. Because males cannot be assigned to both wings of a dormitory, at most males can be assigned to one wing of a dormitory. At the same time, the rules state that there must be exactly three wings with males. Because there are only four dormitories, the situation is restricted, and the following inferences can be drawn:
1. If a dormitory has female students assigned to both wings, then the males must be assigned to one wing in each of the other three dormitories. For example, if Tuscarora South is assigned females (as in question #5), then males must be assigned to Richards South, Veblen North or South, and Wisteria North or South. In question #5, this inference is sufficient to eliminate answer choices (A), (B), and (E). Answer choice (C) can be eliminated by the contrapositive of the final rule, leaving answer choice (D) as correct.
Another way to look at this inference is to assert that only one dormitory can be all-female, and the other three dormitories must each have one male and one female wing.
2. Among any two dormitory pairs, males must always be assigned to at least one wing. For example, with Veblen and Wisteria, at least one of the four wings must always be male.
This inference is directly tested in question #2. With Richards and Tuscarora (only South is relevant since the North wings are assigned to females), at least one must always be male, otherwise there will not be a sufficient number of wings available to house the males. Hence, answer choice (B) is correct.
The final setup to the game appears as follows, but keep in mind the points made in the analysis of the two-value system:
After a careful consideration of the rules, the only two active rules are the fourth and fifth rules. Obviously, you should pay close attention to these rules as you work through the questions, and indeed, the interaction of these rules creates several powerful inferences that are tested throughout the game. In fact, the inferences are so powerful that only a limited number of templates exist for this game, and one approach would be to show the three basic templates:
Template #1: Veblen South is male. Two total solutions.
Template #2: Wisteria North is female, Veblen South is female. Four total solutions.
Template #3: Veblen South is female, Wisteria North is male. Three total solutions.
The choice to show the templates is yours because the game can be done quickly with either approach.
This is an Advanced Linear: Balanced game.
The game scenario and first two rules create an Advanced Linear scenario:
The third rule helpfully assigns females to two of the eight wings:
The fourth rule indicates that if males are assigned to a wing, the other wing must be assigned females. Operationally, this means that males can never be assigned to both wings of a dormitory, which results in a vertical not-block:
The fifth rule is conditional:
- VSM WNM
Of course, if the fifth rule is enacted, and both those wings are assigned males, then by applying the fourth rule, the other wings in those dormitories would be assigned females:
Thus, if Veblen South is assigned males, the Veblen and Wisteria dormitories are fully assigned.
This game also contains a two-value system: each dormitory is assigned either male or female students. Thus, if a dormitory does not have male students, then the dormitory must have female students. As is so often the case, the two-value system can be applied to a conditional rule to create greater insight. Consider the contrapositive of the final rule:
- WNM VSM
The same contrapositive reinterpreted by applying the two-value system:
- WNF VSF
This inference is directly tested in question #3.
Another point of restriction in the game is the males. Because males cannot be assigned to both wings of a dormitory, at most males can be assigned to one wing of a dormitory. At the same time, the rules state that there must be exactly three wings with males. Because there are only four dormitories, the situation is restricted, and the following inferences can be drawn:
1. If a dormitory has female students assigned to both wings, then the males must be assigned to one wing in each of the other three dormitories. For example, if Tuscarora South is assigned females (as in question #5), then males must be assigned to Richards South, Veblen North or South, and Wisteria North or South. In question #5, this inference is sufficient to eliminate answer choices (A), (B), and (E). Answer choice (C) can be eliminated by the contrapositive of the final rule, leaving answer choice (D) as correct.
Another way to look at this inference is to assert that only one dormitory can be all-female, and the other three dormitories must each have one male and one female wing.
2. Among any two dormitory pairs, males must always be assigned to at least one wing. For example, with Veblen and Wisteria, at least one of the four wings must always be male.
This inference is directly tested in question #2. With Richards and Tuscarora (only South is relevant since the North wings are assigned to females), at least one must always be male, otherwise there will not be a sufficient number of wings available to house the males. Hence, answer choice (B) is correct.
The final setup to the game appears as follows, but keep in mind the points made in the analysis of the two-value system:
After a careful consideration of the rules, the only two active rules are the fourth and fifth rules. Obviously, you should pay close attention to these rules as you work through the questions, and indeed, the interaction of these rules creates several powerful inferences that are tested throughout the game. In fact, the inferences are so powerful that only a limited number of templates exist for this game, and one approach would be to show the three basic templates:
Template #1: Veblen South is male. Two total solutions.
Template #2: Wisteria North is female, Veblen South is female. Four total solutions.
Template #3: Veblen South is female, Wisteria North is male. Three total solutions.
The choice to show the templates is yours because the game can be done quickly with either approach.
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Dave Killoran
PowerScore Test Preparation
Follow me on X/Twitter at http://twitter.com/DaveKilloran
My LSAT Articles: http://blog.powerscore.com/lsat/author/dave-killoran
PowerScore Podcast: http://www.powerscore.com/lsat/podcast/
PowerScore Test Preparation
Follow me on X/Twitter at http://twitter.com/DaveKilloran
My LSAT Articles: http://blog.powerscore.com/lsat/author/dave-killoran
PowerScore Podcast: http://www.powerscore.com/lsat/podcast/