## Eighth question set for WBCS Main level Arithmetic

Compulsory paper VI of WBCS Main is on Arithmetic and Test of Reasoning. It has 200 questions to be answered in 180 minutes. In this eighth question set on Arithmetic, 10 selected questions of varied types are included.

The questions are followed by answers and link to the corresponding detailed solution set.

The solution set will provide valuable insight into how the problems are solved quickly in mind followed by detailed explanation and concept elaboration when needed.

Before going through the test, to *refresh concepts* on any topic or to know *how to solve problems at a high speed*, you should refer to **our concept tutorials and articles** listed below.

### Concept tutorials and articles on Arithmetic

#### Number system, fractions and surds

**Numbers, Number system and basic arithmetic operations**

**Factorization or finding out factors**

**Fractions and decimals, basic concepts part 1**

**How to solve surds part 1 rationalization**

**How to solve surds part 2 double square root surds and surd term factoring**

**How to find perfect square root of integers or decimals New**

#### Ratio and proportion and mixing liquids

**Arithmetic problems on mixing liquids and based ages**

**How to solve arithmetic mixture problems in a few steps 1**

**How to solve arithmetic mixture problems in a few steps 2**

#### Percentage

**Basic and rich percentage concepts**

#### Componendo dividendo

**Componendo dividendo explained**

#### Simple interest and compound interest

**Basic and rich concepts on simple interest and compound interest**

#### Work time, work wages and pipes and cisterns

**How to solve arithmetic problems on work time, work wages and pipes and cisterns**

**How to solve time work problems in simpler steps type 1**

**How to solve time work problems in simpler steps type 2**

#### Speed time distance, train problems and boats in rivers

**Basic concepts on speed time distance, train running and boats and rivers**

**How to solve time distance problems in a few simple steps 1**

**How to solve time distance problems in a few simple steps 2**

#### Profit and loss

**How to solve in a few steps profit and loss problems 1**

**How to solve similar problems in a few seconds profit and loss problems 2**

**How to solve difficult profit and loss problems in a few steps 3**

**How to solve difficult profit and loss problems in a few steps 4**

#### Clocks and Calendars

**How to solve Clock problems New**

**How to solve Calendar problems New**

### 8th WBCS Main level Arithmetic question set: time to answer: 10 mins

#### Problem 1

Fraction equivalent of $\displaystyle\frac{2}{3}$% of $\displaystyle\frac{5}{8}$% is,

- $\displaystyle\frac{5}{12}$
- $\displaystyle\frac{1}{240}$
- $\displaystyle\frac{1}{24000}$
- $\displaystyle\frac{4}{37500}$

#### Problem 2

$\displaystyle\frac{4}{5}$th of a number is 64. 70% of the number is,

- 44.8
- 70
- 42
- 56

#### Problem 3

If $\displaystyle\frac{1}{5}:\displaystyle\frac{1}{x}::\displaystyle\frac{1}{x}:\displaystyle\frac{1}{1.25}$, then $x$ is,

- 2.5
- 1.5
- 2
- 3.5

#### Problem 4

What number should come next in the sequence, 4, 5, 7, 10, 11, 13, 16, —?

- 21
- 19
- 18
- 17

#### Problem 5

The perfect square number of least value divisible by 3, 4, 5, 6, and 8 is,

- 900
- 3600
- 1600
- 1200

#### Problem 6

A tree increases annually by $\displaystyle\frac{1}{8}$th of its height. What will be its height after 2 years if it stands today 64 ft high?

- 72 ft
- 74 ft
- 81 ft
- 80 ft

#### Problem 7

In a school, the ratio of boys and girls is $4:5$. When 100 girls leave the school, the ratio becomes, $6:7$. How many boys are there in the school?

- 1200
- 1300
- 1600
- 1500

#### Problem 8

A commission agent allows a rebate of 2% to an investor while the company pays an interest of 15% on the investment. What rate of interest does the investor actually earn on his investment?

- $17$%
- $16\displaystyle\frac{3}{8}$%
- $15$%
- $15\displaystyle\frac{15}{49}$%

#### Problem 9

In what proportion must water be added to spirit to gain 20% by selling it at cost price?

- $1:5$
- $2:3$
- $4:5$
- $3:5$

#### Problem 10

A water tank can be filled up by two pumps in 20 minutes and 30 minutes respectively. They were started together but due to some technical fault, the first pump stopped after some time and the second pump worked alone for the last 10 minutes. How long did they work together?

- 4 minutes
- 8 minutes
- 10 minutes
- 6 minutes

To know how to solve the problems quickly in mind and detailed explanation, you should refer to the corresponding solution set, **WBCS Main Arithmetic solution set 8.**

### Answers to the questions

**Problem 1.** Answer: Option c: $\displaystyle\frac{1}{24000}$.

**Problem 2.** Answer: Option d: 56.

**Problem 3.** Answer: Option a: 2.5.

**Problem 4.** Answer: Option d: 17.

**Problem 5.** Answer: Option b: 3600.

**Problem 6.** Answer: Option c: 81 ft.

**Problem 7.** Answer: Option a: 1200.

**Problem 8.** Answer: Option d: $15\displaystyle\frac{15}{49}$%.

**Problem 9.** Answer: Option a: $1:5$.

**Problem 10.** Answer: Option b: 8 minutes.

### Question and Solution sets on WBCS Main Arithmetic

**WBCS main level Arithmetic Solution set 11**

**WBCS main level Arithmetic Question set 11**

**WBCS main level Arithmetic Solution set 10**

**WBCS main level Arithmetic Question set 10**

**WBCS main level Arithmetic Solution set 9**

**WBCS main level Arithmetic Question set 9**

**WBCS main level Arithmetic Solution set 8**

**WBCS main level Arithmetic Question set 8**

**WBCS main level Arithmetic Solution set 7**

**WBCS Main level Arithmetic Question set 7**

**WBCS Main level Arithmetic Solution set 6**

**WBCS Main level Arithmetic Question set 6**

**WBCS Main level Arithmetic Solution set 5**

**WBCS Main level Arithmetic Question set 5**

**WBCS Main level Arithmetic Solution set 4**

**WBCS Main level Arithmetic Question set 4**

**WBCS Main level Arithmetic Solution set 3**

**WBCS Main level Arithmetic Question set 3**

**WBCS Main level Arithmetic Solution set 2**

**WBCS Main level Arithmetic Question set 2**

**WBCS Main level Arithmetic Solution set 1**

**WBCS Main level Arithmetic Question set 1**