# CRE 1 - 2 Sets | LR - Venn Diagram

**Answer the next 4 questions based on the information given below:**

In a class of 150 students, 90 passed in Maths, 65 passed in English and 15 failed in both the subjects.

**CRE 1 - 2 Sets | LR - Venn Diagram**

How many students passed in both the subjects.

Answer: 20

**Explanation** :

Since 15 failed in both subjects there are 150 – 15 = 135 students who passed in at least one subject.

n(M) = number of students who passed in Maths = 90

n(E) = number of students who passed in English = 65

n(M∩E) = number of students who passed in both Maths as well as English.

n(M∪E) = number of students who passed in at least one of Maths or English = 135

∴ n(M ∪ E) = n(M) + n(E) - n(M∩E)

⇒ 135 = 90 + 65 - n(M∩E)

⇒ n(M∩E) = 90 + 65 – 135 = 20

∴ Number of students who passed in both the subjects = 20

Hence, 20.

Workspace:

**CRE 1 - 2 Sets | LR - Venn Diagram**

How many students passed in English but failed in Maths.

Answer: 45

**Explanation** :

Consider the solution to first question of this set.

We need to figure out the number of students who passed only in English.

= Number of students who passe in English – Number of students who passed in both.

= 65 – 20 = 45

Hence, 45.

Workspace:

**CRE 1 - 2 Sets | LR - Venn Diagram**

How many students failed in exactly one subject.

Answer: 115

**Explanation** :

Consider the solution to first question of this set.

Number of students who failed in only one subject = Number of students who passed in only one subject

= Number of students who passed only in Maths + Number of students who passed only in English

= (65 - 20) + (90 - 20) = 115

**Alternately**,

Number of students who failed in only one subject = Number of students who passed in at least one subject – Number of students who passed in both the subjects.

= 135 – 20 = 115

Hence, 115.

Workspace:

**CRE 1 - 2 Sets | LR - Venn Diagram**

What is the absolute difference between the number of students who failed in Maths and the number of students who failed only in English is?

Answer: 10

**Explanation** :

Consider the solution to first question of this set.

Number of students who failed in Maths = 150 – 90 = 60

Number of students who failed only in English = Number of students who passed only in Maths = 90 – 20 = 70

Difference = 70 – 60 = 10.

Hence, 10.

Workspace:

**Answer the next 5 questions based on the information given below:**

At a party, 144 guests drink only tea, 50% of the guests drink coffee, 25% of the guests drink both tea and coffee and 5% of the guests drink neither tea nor coffee.

**CRE 1 - 2 Sets | LR - Venn Diagram**

What is the total number of guests at the party?

- A.
320

- B.
360

- C.
280

- D.
240

Answer: Option A

**Explanation** :

From the given data, we get the following diagram.

Let the total number of guests be x.

⇒ x = 144 + (25% of x) + (25% of x) + (5% of x)

⇒ x - $\frac{x}{4}$ - $\frac{x}{4}$ - $\frac{x}{20}$ = 144

⇒ $\frac{9x}{20}$ = 144

⇒ x = 320.

The total guets at the party = 320.

Hence, option (a).

Workspace:

**CRE 1 - 2 Sets | LR - Venn Diagram**

How many of the guests drink only tea or only coffee?

- A.
226

- B.
224

- C.
228

- D.
256

Answer: Option B

**Explanation** :

Consider the solution to the first question of this set.

The number of guests who drink only tea or only coffee

= 144 + (25% of 320)

= 144 + 80 = 224.

Hence, option (b).

Workspace:

**CRE 1 - 2 Sets | LR - Venn Diagram**

How many of the guests drink neither tea nor coffee?

- A.
14

- B.
10

- C.
16

- D.
24

Answer: Option C

**Explanation** :

Consider the solution to the first question of this set.

The number of guests who drink neither tea nor coffee

= none = 5% of 320

= 5/100 × 320 = 16.

Hence, option (c).

Workspace:

**CRE 1 - 2 Sets | LR - Venn Diagram**

How many of the guests drink only coffee?

- A.
58

- B.
76

- C.
98

- D.
80

Answer: Option D

**Explanation** :

Consider the solution to the first question of this set.

The number of guests who drink only coffee = 25% of 320 = 80.

Hence, option (d).

Workspace:

**CRE 1 - 2 Sets | LR - Venn Diagram**

How many of them drink at least one of the two?

- A.
306

- B.
288

- C.
256

- D.
304

Answer: Option D

**Explanation** :

Consider the solution to the first question of this set.

The number of guests who drink at least one of the two

= 144 + (25% of 320) + (25% of 320)

= 144 + 80 + 80 = 304.

**Alternately,**

The number of guests who drink at least one of the two = Total number of guest – those guests who drink none of tea or coffee.

= 320 – (5% of 320) = 320 – 16 = 304.

Hence, option (d).

Workspace:

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