A candidate with **quantitative aptitude** knowledge will be in a better position to analyse and make sense of the given data. Quantitative Aptitude knowledge is an **important** measure for a prospective business executive’s **abilities**.

The article **SSC CPO Quantitative Aptitude Quiz 3** provides Quantitative Aptitude questions with answers useful to the candidates preparing for** Competitive exams, Entrance exams, Interviews** etc. The article **SSC CPO Quantitative Aptitude Quiz 3** will assist the students to know the expected questions from **Quantitative Aptitude**.

- A. 10

B. 11.5

C. 12

D. 10.5

**Answer**: Option D

**Explanation**:

Average of the first ‘n’ natural numbers = (n + 1)/2

We get \(\frac {(20 + 1)}{2}\) = 10.5

**2. The average of 13 numbers is 60. Average of the first 7 of them is 57 and that of the last 7 is 61. Find the 8th number?**

- A. 46

B. 32

C. 68

D. 51

**Answer**: Option A

**Explanation**:

Sum of all the 13 numbers = 13 * 60 = 780

Sum of the first 7 of them = 7 * 57 = 399

Sum of the last 7 of them = 7 * 61 = 427

So, the 8th number = 427 + 399 – 780 = 46.

**3. A batsman makes a score of 64 runs in the 16th innings and thus increased his average by 3. Find his average after the 16th inning?**

- A. 17

B. 29

C. 18

D. 19

**Answer**: Option D

**Explanation**:

Let the average after the 16th inning be P.

So, the average after the 15th inning will be (P-3) Hence, 15(P-30) + 64 = 16P => P = 19

**4. The average marks of a class of 30 students is 40 and that of another class of 50 students is 60. Find the average marks of all the students?**

- A. 50

B. 47.5

C. 59

D. 52.5

**Answer**: Option D

**Explanation**:

∵Let after x hours the second train will meet the first train.

Sum of the marks for the class of 30 students = 30 * 40 = 1200

Sum of the marks for the class of 50 students = 50 * 60 = 3000

Sum of the marks for the class of 80 students =

1200 + 3000 = 4200

Average marks of all the students = \(\frac {4200}{80}\) = 52.5

**5. The average salary of a person for the months of January, February, March and April is Rs.8000 and that for the months February, March, April and May is Rs.8500. If his salary for the month of May is Rs.6500, find his salary for the month of January?**

- A. 3000

B. 2500

C. 4500

D. 5000

**Answer**: Option C

**Explanation**:

Sum of the salaries of the person for the months of January, February, March and April = 4 * 8000 = 32000 —-(1)

Sum of the salaries of the person for the months of February, March, April and May = 4 * 8500 = 34000 —-(2)

(2)-(1) i.e. May – Jan = 2000

Salary of May is Rs.6500

Salary of January = Rs.4500

- A. 150

B. 200

C. 250

D. 275

**Answer**: Option B

**Explanation**:

30% ———— 50

45% ———— 25

———————-

15% ————- 75

30% ————– ?

150 + 50 = 200 Marks

**2. After 38 liters of petrol were poured into the tank, it was still 5% empty. How much petrol must be poured into the tank in order to fill it?**

- A. 38 liters

B. 40 liters

C. 38.5 liters

D. 2 liters

**Answer**: Option D

**Explanation**:

95% ———– 38

5% ———— ? => 2 liters

**3. The population of a town is 45000; 5/9th of them are males and the rest females 40% of the males are married. What is the percentage of married females?**

- A. 60%

B. 50%

C. 45%

D. 40%

**Answer**: Option B

**Explanation**:

Male = 45,000* \(\frac {5}{9}\) = 25,000

Female = 45,000* \(\frac {4}{9}\) = 20,000

Married Male = 25,000* \(\frac {40}{100}\) = 10,000

Married Female = 10,000

20,000 ———— 10,000

100 ————- ? => 50%

**4. The salary of a worker is first increased by 30% and afterwards reduced by 30%. What is net change in his salary?**

- A. 90% increase

B. 45% increase

C. 9% decrease

D. Same as before

**Answer**: Option C

**Explanation**:

\(\frac {(30 * 30)}{100}\) = 9% decrease

**5. A person spends 1/5th of his income on the education of his children, and 20% of the remaining on food. If he is left with Rs.576 find his income?**

- A. Rs.900

B. Rs.800

C. Rs.500

D. Rs.1000

**Answer**: Option A

**Explanation**:

X *\(\frac {4}{5}\) *\(\frac {80}{100}\) = 576

X = 14400/16

X = 900

- A. 3

B. 4

C. 5

D. 9

**Answer**: Option B

**Explanation**:

3, 5, 9 and 7 are odd numbers, but not 4.

**2. Find the one which does not belong to that group ?**

- A. 27

B. 37

C. 47

D. 67

**Answer**: Option A

**Explanation**:

37, 47, 67 and 17 are prime numbers but not 27

**3. Find the one which does not belong to that group ?**

- A. 16

B. 28

C. 36

D. 64

**Answer**: Option C

**Explanation**:

16, 36, 64 and 4 are perfect squares but not 28

**4. Find the one which does not belong to that group ?**

- A. 41

B. 43

C. 53

D. 57

**Answer**: Option D

**Explanation**:

41, 43, 47 and 53 are prime numbers, but not 57.

**5. Find the one which does not belong to that group ?**

- A. 36

B. 49

C. 64

D. 81

**Answer**: Option B

**Explanation**:

36 = \({6}^{2}\), 49 = \({7}^{2}\), 64 = \({8}^{2}\), 81 = \({9}^{2}\) and 100 = \({10}^{2}\).

36, 64, 81 and 100 are squares of composite numbers, but not 49.