Questions & Answers: "Decimals and Percentages"

Complete guide to "Decimals and Percentages" for Math students. Below you will find important questions and model answers to help you prepare.

14 Questions

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Question 1

1 Mark

If 25% of 780 = M% of 1950 then ‘M’ = ?

Options

Option A is correct

10

Option B

12

Option C

8

Option D

14

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Question 2

1 Mark

Every year the population of a town decreases by 5% due to migration of the people. In the year 2022 the population was 9025. Find the population of the town in the year 2020?

Options

Option A is correct

10,000

Option B

11,000

Option C

11,025

Option D

10,250

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Question 3

1 Mark

Find the value of 31.25%.

Options

Option A is correctDiagram for Option A
Option B Diagram for Option B
Option C Diagram for Option C
Option D Diagram for Option D
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Question 4

1 Mark

Ajay scored 25% marks less than Balbir. Then Balbir scored how much percentage of marks more than Ajay?

Options

Option A Diagram for Option A
Option B Diagram for Option B
Option C Diagram for Option C
Option D is correctDiagram for Option D
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Question 5

1 Mark

The rate of tickets of a bus are increased by 20%. After six months, the rate of tickets again increased by 10% then what is the percentage increase in the original rate of tickets.

Options

Option A

30 %

Option B is correct

32 %

Option C

25 %

Option D

35 %

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Question 6

1 Mark

The population of a town was 75000. This population is increased by 10% next year. After that year, the population decreased by 8%. In the third year the population is increased by 5% then at the end of third year, what will be the population?

Options

Option A

935550

Option B

78000

Option C is correct

79695

Option D

77950

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Question 7

1 Mark

3.9% of 1530 = ? (Choose two correct options.)

Options

Option A is correctDiagram for Option A
Option B Diagram for Option B
Option C is correctDiagram for Option C
Option D Diagram for Option D
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Question 8

1 Mark

60 l. milk contains 15% fats, and 40 l. milk contains 8% fats. If these two milk are mixed together, then what will be the % of fats contained in the mixture?

Options

Option A

87.8 %

Option B is correct

12.2 %

Option C

1220 %

Option D

122 %

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Question 9

1 Mark

As the rate of ticket of a play increased by 25%, the sale reduced by 15%. What is the rise or fall in the total income?

Options

Option A is correct

6.25 % rise

Option B

6.25 % fall

Option C

12.5 % rise

Option D

12.5 % fall

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Question 10

1 Mark

If 240 litre milk containing 8% fat is mixed with 160 litre milk containing 15% fat. What will be the percentage of fat in the mixture.

Options

Option A

10.5

Option B

10.6

Option C

10.7

Option D is correct

10.8

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Question 11

1 Mark

Due to 20% increase in the price of a ticket, the sale was decreased by 10%. Find by how much percentage the income was increased or decreased?

Options

Option A

8% decrease

Option B is correct

8% increase

Option C

7% decrease

Option D

7% increase

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Question 12

1 Mark

If 400 litre milk containing 11% fat is mixed with 600 litre milk containing 8% fat. What will be the percentage of fat in the mixture? (Select two correct alternatives)

Options

Option A

8.4

Option B is correct

9.2

Option C is correct

\frac{46}{5}

Option D

\frac{42}{5}

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Question 13

1 Mark

Find the value of 0.545454+0.5454+0.540.545454 + 0.5454 + 0.54

Options

Option A is correct

1.630854

Option B

1.531854

Option C

1.631854

Option D

1.631845

Explanation

To find the sum, align the decimal points and add the numbers: 0.545454+0.545400+0.540000=1.6308540.545454 + 0.545400 + 0.540000 = 1.630854.

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Question 14

1 Mark

Due to increase in the prices of fruits by 20%, the sale was decreased by 10%. Find the percent increase or decrease in the income of the fruitseller.

Options

Option A

10% increase

Option B is correct

8% increase

Option C

8% decrease

Option D

10% decrease

Explanation

Let the original price of fruits be PP and the original quantity sold be QQ.The original income (IoriginalI_{original}) of the fruitseller is Ioriginal=P×QI_{original} = P \times Q.The prices of fruits increased by 20%, so the new price (PnewP_{new}) is:Pnew=P+0.20P=1.20PP_{new} = P + 0.20P = 1.20PThe sale (quantity) decreased by 10%, so the new quantity sold (QnewQ_{new}) is:Qnew=Q−0.10Q=0.90QQ_{new} = Q - 0.10Q = 0.90QThe new income (InewI_{new}) of the fruitseller is:Inew=Pnew×Qnew=(1.20P)×(0.90Q)=(1.20×0.90)×(P×Q)=1.08PQI_{new} = P_{new} \times Q_{new} = (1.20P) \times (0.90Q) = (1.20 \times 0.90) \times (P \times Q) = 1.08PQTo find the percent change in income, we use the formula: Percent Change=Inew−IoriginalIoriginal×100%\text{Percent Change} = \frac{I_{new} - I_{original}}{I_{original}} \times 100\% Percent Change=1.08PQ−PQPQ×100%\text{Percent Change} = \frac{1.08PQ - PQ}{PQ} \times 100\% Percent Change=0.08PQPQ×100%\text{Percent Change} = \frac{0.08PQ}{PQ} \times 100\% Percent Change=0.08×100%\text{Percent Change} = 0.08 \times 100\% Percent Change=8%\text{Percent Change} = 8\%Since the result is positive, it is an 8% increase in income.

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