Logic Games

Question 1

Sufficient Conditions

Answer 1

• If clause
• Trigger
  A –> b

Question 2

Necessary Conditions

Answer 2

• Then clause
• Result
  a –> B

Question 3

Forming contrapositive

Answer 3

• reverse the terms
• negate all terms
• change ANDs to ORs and vice versa

Question 4

Basic If/Then

Answer 4

if A then B
A –> B
-B –> -A

All C are D
C –> D
-D –> -C

Question 5

Only/ Unless

Answer 5

Only, Only if = THEN
Unless - IF NOT

Only E are F
F –> E
-E –> -F

G only if H
G –> H
-H –> - G

No I unless J
I –> J
-J –> -I

Question 6

Challenging If/Then

Answer 6

Neither…Nor = AND

No K is L
K –> - L
L –> - K

M if N or if O
N or M –> M
-M –> -N and -)

If P or Q then neither R nor S
P or Q –> -R and -S
R or S –> -P and -Q

T if, but only if, U
T --> U
U --> T
-U --> -T
-T --> -U

Question 7

Logic Games Method

Answer 7

1) Overview (SEAL: situation, entities, action, limitations)
2) sketch (strict vs. loose)
3) Rules
4) Deductions (BLEND: blocks of entities, limited options, established entities, numbers duplications)
5) Questions (acceptability first!)

Question 8

What is the EARLIEST position an entity can appear?

Answer 8

The EARLIEST possible placement for any entity in a sequence:

(# of entities that MUST be before it) + 1

Question 9

What is the LATEST position an entity can appear?

Answer 9

The LATEST possible placement for an entity in a sequence:

total # of entities) - (the # of entities that MUST be after it