Solving two-variable logic games

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LSAT Logic Games › Solving two-variable logic games

Questions 1 - 10
1

A school is holding tryouts for seven athletes – Eric, Fred, Greg, Ian, John, Kevin, and Merlin – for the varsity and JV track teams. Which team the athletes can join is determined by their 40 yard dash time; the three fastest will join the varsity team and the four slowest the JV team, subject to the following conditions:

Fred has a faster time than Ian.
Eric has a faster time than Ian, but a slower time than Greg
Greg has a faster time than Fred, but a slower time than John.
Kevin is part of the JV team.

Which of the following athletes CANNOT be on the varsity team?

Ian

Greg

Eric

Merlin

Fred

Explanation

Using the J - G - E/F - I combination of the first three rules, we can see that there are at least four athletes that must have faster times than Ian. As there are only three spots on the varsity team, it is impossible for Ian to be placed onto the varsity team in any scenario.

2

A barista has seven boxes of tea and coffee of varying types, which she places in a line behind the counter. There are four types of coffee: Colombian, Dark, Espresso, and French. There are three types of tea: Green, Herbal, and Vanilla. The following rules apply:

A box of tea must be fifth

No tea may be placed next to another tea

Herbal may not be next to either Colombian or Espresso

At least two boxes must be between Colombian and Dark

Which of the following cannot be true?

Coffee is both first and last

Coffee is both first and sixth

Two boxes of coffee are next to each other

Tea is both first and last

Coffee is third and fourth

Explanation

If coffee were first and last, then two boxes of tea would need to be next to each other. Since one box would need to be fifth and since we could not put tea first or seventh, there is no way to separate all the boxes of tea.

3

Three circus performers—Flo, Genie, and Kyle—will perform the following six circus acts: acrobatics; ball juggling; clowning; dunking; elephant demonstrations; fire twirling. Each act is performed only once in any given show, and only one act is performed at a time. The following conditions dictate the sequencing of these acts:

  • Flo performs exactly one act before Genie performs any of her acts
  • Flo does not perform first and he does not perform last
  • Genie does not do acrobatics and ball juggling
  • Kyle does not do acrobatics and elephant demonstrations
  • Ball juggling is performed immediately after the elephant demonstrations

If Kyle performs last, then which of the following must be true?

Genie performs some time after Kyle and Flo.

Genie performs second.

Genie performs immediately after Kyle.

Genie does elephant demonstrations immediately before Kyle performs.

Flo does ball juggling.

Explanation

This question calls for an answer that reflects what must happen, not what could happen. We know that Kyle must go first, so Kyle occupies slots 1 and 6. We know that Flo must go before Genie performs her first act. So Genie cannot occupy slot 2. That means Genie must perform after some time after Kyle and Flo, which is the credited response.

4

Exactly five men—Adam, Ben, Carlos, David, and Eric—and five women—Liza, Michelle, Nicole, Olivia, and Patricia—are scheduled to take ballroom dance classes. There is one class offered each day—Monday, Tuesday, Wednesday, Thursday, and Friday—for a total of five classes. Every class has exactly one man and one woman. Every person participates in exactly one class with the following conditions:

Ben dances one day before Olivia.

Carlos and Nicole attend class on the same day.

Adam dances on Friday.

There is exactly one day between the days Ben and Carlos dance.

Which is a possible and acceptable partial schedule for the week?

Monday: Ben and Michelle

Tuesday: David and Olivia

Wednesday: Carlos and Nicole

Monday: Carlos and Nicole

Tuesday: David and Olivia

Wednesday: Ben and Patricia

Monday: David and Patricia

Tuesday: Carlos and Michelle

Wednesday: Eric and Nicole

Monday: David and Patricia

Tuesday: Ben and Michelle

Wednesday: Adam and Olivia

Monday: Eric and Michelle

Tuesday: Carlos and Nicole

Wednesday: Ben and Patricia

Explanation

All of the incorrect answers break one of the constraits placed on the order.

Monday: Carlos and Nicole

Tuesday: David and Olivia

Wednesday: Ben and Patricia

(Ben must dance one day before Olivia)

Monday: David and Patricia

Tuesday: Carlos and Michelle

Wednesday: Eric and Nicole

(Carlos and Nicole must dance on the same day)

Monday: David and Patricia

Tuesday: Ben and Michelle

Wednesday: Adam and Olivia

(Adam must dance on Friday)

Monday: Eric and Michelle

Tuesday: Carlos and Nicole

Wednesday: Ben and Patricia

(The must be one day between Ben and Carlos)

5

A chef is arranging spices on a shelf. Four of the spices are in large jars: garlic, oregano, pepper, and salt. Three of the spices are in small jars: basil, cumin, and mint. The following conditions apply:

A large jar must be first or fourth

Pepper must come after cumin but before basil

The jar of salt must be the first large jar in the line

Basil cannot be immediately before or after garlic

If the rules are changed so that basil must come directly after garlic, and if all other rules remain the same, which of the following cannot be true?

garlic is fourth

mint is first

cumin is fourth

pepper is fifth

mint is second

Explanation

If garlic and basil must be next to each other, then there are now five spices that must come after salt. Only four spices can come after salt when salt is third, so salt cannot be third.

6

A human resources manager must schedule a round of interviews during a particular day. Six different time slots are available in the afternoon and are numbered one through six in sequential order. Six candidates - Joe, Jim, Mary, Bob, Jess, and Sue - must be scheduled during the afternoon. Only one candidate can occupy each interview slot. The assignment of interview slots is subject to the following restrictions:

  • Either Mary or Bob must occupy the second time slot.
  • Joe must occupy the sixth time slot.
  • Mary and Bob cannot occupy consecutive time slots.
  • Jim and Mary must occupy consecutive time slots.
  • Sue must be interviewed before Jess.

If Jim is assigned to the fourth slot, which of the following must be true?

Mary must occupy the fifth slot.

Mary must occupy the third slot.

Sue must occupy the third slot.

Jess must occupy the first slot.

Bob must occupy the third slot.

Explanation

The only restriction that involves Jim is that he and Mary must occupy consecutive slots. Therefore, if Jim occupies the fourth slot, Mary must occupy the third or fifth slot. Since Mary can't be in the second slot, Bob must be assigned to this slot. Lastly, Mary and Bob cannot occupy consecutive slots. So if Bob is in the second slot, Mary cannot be in the third slot. Mary must be in the fifth time slot. Now the 2nd, 4th, 5th, and 6th slots are all accounted for. Finally, since Sue must be interviewed before Jess, Sue must be 1st and Jess must be 3rd.

7

A chef is arranging spices on a shelf. Four of the spices are in large jars: garlic, oregano, pepper, and salt. Three of the spices are in small jars: basil, cumin, and mint. The following conditions apply:

A large jar must be first or fourth

Pepper must come after cumin but before basil

The jar of salt must be the first large jar in the line

Basil cannot be immediately before or after garlic

When pepper is third, which of the following could be true?

oregano is fifth

mint is second

garlic is second

cumin is fifth

oregano is second

Explanation

When pepper is third, salt and cumin are the only spices to come before it. As a result, oregano, garlic, and mint cannot be second. Further, cumin must come before pepper and, therefore, cannot be fifth. Oregano could be fifth.

8

A school is holding tryouts for seven athletes – Eric, Fred, Greg, Ian, John, Kevin, and Merlin – for the varsity and JV track teams. Which team the athletes can join is determined by their 40 yard dash time; the three fastest will join the varsity team and the four slowest the JV team, subject to the following conditions:

Fred has a faster time than Ian.
Eric has a faster time than Ian, but a slower time than Greg
Greg has a faster time than Fred, but a slower time than John.
Kevin is part of the JV team.

Which of the following could be an accurate list of the team rosters, arranged from fastest to slowest?

Varsity: John, Merlin, Greg;
JV: Fred, Eric, Kevin, Ian.

Varsity: John, Fred, Greg;
JV: Merlin, Eric, Ian, Kevin.

Varsity: Merlin, John, Greg;
JV: Kevin, Eric, Ian, Fred.

Varsity: Greg, John, Fred;
JV: Eric, Ian, Kevin, Merlin.

Varsity: John, Merlin, Ian;
JV: Greg, Fred, Eric, Kevin.

Explanation

Each of the incorrect answers violates one of the stated conditions:

(Varsity: John, Fred, Greg;
JV: Merlin, Eric, Ian, Kevin.) - Greg has a faster time than Fred.

(Varsity: Merlin, John, Greg;
JV: Kevin, Eric, Ian, Fred.) - Fred has a faster time than Ian.

(Varsity: Greg, John, Fred;
JV: Eric, Ian, Kevin, Merlin.) - John has a faster time than Greg.

(Varsity: John, Merlin, Ian;
JV: Greg, Fred, Eric, Kevin.) - Ian has a slower time than both Fred and Greg.

The correct answer does not violate any of the conditions.

9

A photographer is hanging six portraits on the wall in a straight line. The portraits are of six family members: Lily, Mildred, Nancy, Owen, Peter and Quentin. The order in which the portraits are hung must conform to the following restrictions:

Mildred's portrait must be either first or last

There must be exactly one portrait between Nancy and Quentin

Nancy's portrait must come after Lily's but before Quentin's

Which of the following is an acceptable order in which the portraits could be hung?

Mildred, Lily, Owen, Nancy, Peter, Quentin

Lily, Mildred, Nancy, Owen, Quentin, Peter

Lily, Nancy, Quentin, Peter, Owen, Mildred

Mildred, Nancy, Lily, Quentin, Owen, Peter

Lily, Quentin, Peter, Nancy, Owen, Mildred

Explanation

Any option without Mildred being first or last is immediately taken out. Any option without one space between Nancy and Quentin is taken out, and any option that has Quentin appearing before Nancy is taken out. Any option that doesn't have Lily appearing before Nancy is taken out, leaving only the correct answer as an option.

10

Three circus performers—Flo, Genie, and Kyle—will perform the following six circus acts: acrobatics; ball juggling; clowning; dunking; elephant demonstrations; fire twirling. Each act is performed only once in any given show, and only one act is performed at a time. The following conditions dictate the sequencing of these acts:

  • Flo performs exactly one act before Genie performs any of her acts
  • Flo does not perform first and he does not perform last
  • Genie does not do acrobatics and ball juggling
  • Kyle does not do acrobatics and elephant demonstrations
  • Ball juggling is performed immediately after the elephant demonstrations

Which one of the following could be true?

Fire twirling is the first act performed.

Acrobatics is the first act performed.

Ball juggling is the second act performed.

Elephant demonstrations is the first act performed.

Elephant demonstrations is the last act performed.

Explanation

Flo does acrobatics, so it cannot come first.

For ball juggling to go second, elephant demonstrations would have to first. But elephant demonstrations can't go first because Kyle must go first and he doesn't do elephant demonstrations.

Finally, elephant demonstrations can't go last because ball juggling must follow.

Consequently, the only option left is fire twirling going first---and that is the credited response.

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