Chapter 5: VENN DIAGRAMS

Introduction

The verbal deduction type questions can be easily solved using venn diagrams and without having to know the complicated formulae.

Example:
1. A few diabetics are insulin dependent. Some insulin dependents eat sweets. A few diabetics eat sweets.

The Venn diagram looks like below. Here note that there could be other cases too were a venn diagram can be drawn to show overlapping between diabetics, insulin dependents and sweet eaters but we have to consider extreme cases. Hence proved that above statement is wrong.

Example 2:
Madrid is built of cement. some cement are colored. Madrid is colored.
The Venn diagram shows Madrid isn't colored in all cases of Venn diagram.

Example 3: No stock broker tells truth. all players tell truth. no stock broker is player.
The Venn diagram shows that the statement is true for all cases. Although common sense can be used for this statement too.

Example 4: Some books are pens. All books are chocolates. Some chocolates are pens.
Thus the Venn diagram shows that the statement remains true for all.

Example 5: Many automobiles are not four wheelers. All cars are automobiles. Some cars are not four wheelers.

The Venn diagram shows that all cars are not four wheelers is also possible so the some cars are not four wheelers implies some cars are four wheelers and so isn't true.
Example 6: Clerks are typists; typists are computer savvy; clerks are not computer savvy.

The Venn diagram shows all clerks are computer savvy.

Each question contains four arguments of three sentences each. Choose the set in which the third statement is a logical conclusion of the first two.

Q.A. Some Xs are Ps. Some Ps are Ys. Some Xs are Ys.
B. All Sonas are bright. Some bright are crazy. Some Sonas are crazy.
C. No faith is strong. Only strong have biceps. No faith has biceps.
D. All men are weak. Some weak are strong. Some strong are weak.

1. A and D

2. C only

3. D only

4. None of these

Ans.b

Q.A. Some icicles are cycles. All cycles are men. Some icicles are men.
B. All girls are teeth. No teeth is yellow. No girls are yellow.
C. No hand is foot. Some foot are heads. Some hands are heads.
D. Every man has a wife. All wives are devoted. No devoted has a husband.

1. A, B and C

2. A and B

3. C and B

4. A, B and C and D

Ans.b

Q.A. No sun is not white. All moon is sun. All moon is white.
B. All windows are open. No open space is allocated. All window is closed space.
C. No German can fire. All Americans bombard. Both, Germans and Americans can fight.
D. No X is Z. No Z is Y. No X is Y.

1. A only

2. B only

3. C only

4. D only

Ans.a

Q.A. All Ts are square. All squares are rectangular. All Ts are rectangular.
B. Some fat are elongated. Some elongated things are huge. Some fat are huge.
C. Idiots are bumblers. Bumblers fumble. Idiots fumble.
D. Water is good for health. Health foods are rare. Water is rare.

1. D only

2. C only

3. Both A and C

4. All of these

Ans.c