Logical Reasoning

Question:2, 6, 12, 20, 30, ?

What's the next number?

Solution:

Let's look at the differences:

6 - 2 = 4

12 - 6 = 6

20 - 12 = 8

30 - 20 = 10

Differences: 4, 6, 8, 10 (even numbers in sequence)

Next difference = 12

∴ Next number = 30 + 12 =42

Question:A, C, F, J, O, ?

What is the next letter?

Solution:

Letter slots: A=1, C=3, F=6, J=10, O=15

Differences: 2, 3, 4, 5

Next difference = 6

Next place = 15 + 6 = 21

21st character =U

Question:If the word BOOK is coded as CPPL, how will HAND be coded?

Solution:

BOOK → Let us see the CPPL rule:

B → C (+1)

O → P (+1)

O → P (+1)

K → L (+1)

Rule: Each letter is +1 space ahead

For HAND:

H → I (+1)

A → B (+1)

N → O (+1)

D → E (+1)

∴ HAND =IBOE

Question:Ram is standing towards north. He took a right turn and traveled 5 km. walked Then turn left and drive for 3 km. walked Which direction is he facing now?

Solution:

1. Start: Northward

2. Turn right: North →East

3. 5 km. Walked (to the east)

4. Turn left: East →North

5. 3 km. Walked (in north direction)

∴ Final direction =North

Question:A is the father of B. C is daughter of B. D is C's brother. E is wife of D. What is the relationship of A to E?

Solution:

1. A = B's father

2. C = daughter of B (granddaughter of A)

3. D = brother of C (son of B, grandson of A)

4. E = D's wife (D's wife = A's grandson's wife)

∴ E is = to AGrandson's wife

Question:Ram is 10th to the left and 15th to the right in a row. How many people are in the queue?

Solution:

Formula: Total = Left + Right - 1

Total = 10 + 15 - 1

total =24 people

Question:5 people are sitting in a row. A is to the right of B. C is to the left of D. B is to the right of E. A is to the left of E. Who is sitting in the middle?

Solution:

Let's set the information:

1. A is to the right of B: B _ A

2. B is to the right of E: E _ B _ A

3. A to the left of E: E _ _ A (affirmation)

4. C, left of D: C D

Final sequence: C D E B A or E C D B A

in the middle =E or D

Question:16 : 4 :: 64 : ?

Solution:

Let's see the relationship:

16 = 4² → 4 = √16

Likewise:

64 = 8² → ? = √64 =8

Question:2, 5, 10, 17, 26, 37, 50

Which of these is irregular?

Solution:

Let's see the sequence rule:

2 = 1² + 1

5 = 2² + 1

10 = 3² + 1

17 = 4² + 1

26 = 5² + 1

37 = 6² + 1

50 = 7² + 1 (but 7² = 49, 49+1 = 50 ✓)

All right! Recheck:

Differences: 3, 5, 7, 9, 11, 13 (odd numbers)

If all is true then the question is false or all is true!

Question:A, B, C, D, E are five friends. Among them:

• A is taller than B
• C is taller than D
• D is taller than A
• E is taller than everyone else

Who is the shortest?

Solution:

Let's sort:

1. A > B

2. C > D

3. D > A (so D > A > B)

4. E > all

5. C > D > A > B

Final order: E > C > D > A > B

Very low height =B

1. 3, 9, 27, 81, ? →243(×3 row)
2. Z, X, V, T, ? →R(-2 row)
3. CAT + 2 Code →ECV
4. North → 2 Turn right →South
5. Father's son's son →Grandson
6. Left=12, Right=8 → Total =19

Example:

Left=10, Right=? Total=25

Right = 25 - 10 + 1 =16

Quick Check:

16:4 → √ relationship → 64:8 ✓

Example:

2, 3, 5, 7, 9, 11 → 9 is irregular (not prime)

Example:

East 3 km, North 4 km.

Distance = √(9 + 16) = √25 =5 km

• Opposite letter:Sum = 27
• Direction:N-E-S-W clock
• Rank:Left + Right - 1
• EJOTY:5, 10, 15, 20, 25
• Class:1, 4, 9, 16, 25, 36, 49, 64, 81, 100
• Weight:1, 8, 27, 64, 125
• Weather:2, 3, 5, 7, 11, 13, 17, 19, 23, 29
• 2 Turn right:opposite direction