WBCS Math Question set for Arithmetic Practice 6

6th selected WBCS math question set for Arithmetic practice

10 WBCS math questions with answers are on ratio, number system, mixture, series, pipes cisterns, fractions, train running, boats rivers.

It should be useful for prelims of other competitive exams also.

The solution set (linked at the end) explains how to solve the questions quickly in mind.

To refresh concepts on any topic and to know how to solve the questions quickly, refer to the concept articles listed below.

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Concept tutorials and articles on Arithmetic

Number system, fractions and surds

Numbers, Number system and basic arithmetic operations

Factorization or finding out factors

HCF and LCM

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

Ratio and proportion and mixing liquids

Ratio and proportion

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

How to solve Calendar problems

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6th WBCS arithmetic practice question set: time to answer: 10 mins

Problem 1

If the ratio of three numbers are $3:4:5$ and their LCM is 1200, then the smallest number is,

1. 80
2. 60
3. 120
4. 100

Problem 2

The least number which when diminished by 5 is divisible by each of 21, 28, 36, 45 is,

1. 425
2. 1260
3. 1265
4. 1259

Problem 3

A container contains $x$ litres of milk. $y$ litres of milk was taken out and replaced by water. How much milk will be there in the container after carrying out this process $(n-1)$ times?

1. $x\left(1-\displaystyle\frac{y}{x}\right)^n$ litres
2. $x\left(1-\displaystyle\frac{y}{x}\right)^2$ litres
3. $x\left(1-\displaystyle\frac{y}{x}\right)^{n-1}$ litres
4. $x\left(1-\displaystyle\frac{y}{x}\right)^3$ litres

Problem 4

What number should come next in the sequence, 6, 18, 72, 360, 2160...?

1. 15120
2. 12120
3. 13120
4. 14120

Problem 5

A pump can fill a tank with water in 2 hrs. Because of a leak developed in the tank, it takes now $2\displaystyle\frac{1}{2}$ hrs to fill the tank. The leak will empty the full tank with pump not running, in,

1. $8$ hrs
2. $10$ hrs
3. $14$ hrs
4. $2\displaystyle\frac{1}{3}$ hrs

Problem 6

Gold is 19 times as heavy as water and copper is 9 times as heavy as water. The ratio in which these two metals are to be mixed so that the mixed alloy becomes 15 times as heavy as water is,

1. 2 : 3
2. 1 : 2
3. 3 : 2
4. 19 : 135

Problem 7

A student was asked to divide a number by 3, but instead of dividing he multiplied it by 3 and got 29.7 as the result. The correct answer would be,

1. 9.9
2. 9.3
3. 9.8
4. 3.3

Problem 8

Which of the following fractions is the largest?

1. $\displaystyle\frac{7}{8}$
2. $\displaystyle\frac{63}{80}$
3. $\displaystyle\frac{31}{40}$
4. $\displaystyle\frac{13}{16}$

Problem 9

A fisherman can row 2 km against the stream in 20 minutes and return in 15 minutes. The speed of the boat in still water is,

1. $2$ km per hour
2. $3$ km per hour
3. $1\displaystyle\frac{1}{2}$ km per hour
4. $7$ km per hour

Problem 10

Two trains running in opposite direction cross a man standing on the platform in 27 secs and 17 secs respectively and they cross each other in 23 secs. The ratio of their speeds is,

1. 1 : 3
2. 3 : 2
3. 2 : 3
4. 3 : 4

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Related detailed solution set

Refer to the companion Solution to WBCS Math Question set for Arithmetic Practice 6 for detailed explanation of the concepts and quick methods of solution.

Answers to questions

Problem 1. Answer: Option b: 60.

Problem 2. Answer: Option c: 1265.

Problem 3. Answer: Option c: $x\left(1-\displaystyle\frac{y}{x}\right)^{n-1}$ litres.

Problem 4. Answer: Option a: 15120.

Problem 5. Answer: Option b: 10 hrs.

Problem 6. Answer: Option c: 3 : 2.

Problem 7. Answer: Option d: 3.3.

Problem 8. Answer: Option a: $\displaystyle\frac{7}{8}$.

Problem 9. Answer: Option d: $7$ km per hour.

Problem 10. Answer: Option b: 3 : 2.

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Question and Solution sets on WBCS Arithmetic

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WBCS Main level Arithmetic Solution set 1

WBCS Main level Arithmetic Question set 1

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