# latest material on percentages

## To convert fraction into percentage multiple the given fraction with 100%

50% = 50/100 = 1/21/2 = 1/2(100%) = 50%

EX:

convert the folowing percentages into fraction

1) 60% = 60/100 = 3/5

2) 12.5 % = 12.5/100 = 5/40 = 1/8

3) 33 (1/3)% = 100/3 = 1/3

4) 16(2/3)% = 50/(3*100) = 1/6

EX:

convert the following fractions into percentage

1) (3/4)*100 = 75 %

2) (4/5) * 100 = 80%

3) (2/3) * 100 = 200/3 = 66(2/3)%

4) (1/5) *100 = 20%

5) (1/12)*100 = 25/3 % = 8 (1/3)%

NOTE:

50% = 1/2

25% = 1/4

12(1/2)% = 1/8

6(1/4)% = 1/16

66 (2/3)% = 2/3

33(1/3)% = 1/3

16(2/3) % = 1/6

8(1/3)% = 1/12

75% = 3/4

14 (2/7)% = 1/7

11(1/9)% = 1/9

9 (1/11)% = 1/11

NOTE:

1/1 = 100%

1/2 = 50%

1/3 = 75%

1/4 = 25%

1/5 = 20%

1/6 = 16 (2/3)%

1/7 = 14(2/7)%

1/8 = 12(1/2)%

1/4 = 11(1/4)%

1/10 = 10%

1/11 = 9(1/11)%

1/12 = 8(1/3)%

FORMULAE:

1 x%y = (x/100)y

(xy)/100

2 x is what percentage of y

what = (100%x)/y

is/of just remember

EG:

IN 250 FIND 30 % VALUE?

10% = 25

30 % = 75

EG:

IN 360 FIND 15%

10% = 36

5% = 18

15% = 54

EG:

IN 450 FIND 22 % VALUE?

10% = 45

20% = 90

2% = 9

......

99

IN 240 FIND 19%?

20% 48

-1% 2.4

........

45.6

EG:

30 % OF 120 = 36

EG:

IN A CLASS BOYS AND GIRLS ARE IN THE RATIO 3:2 then find percentage of boys

total 5 parts

boys (3/5) * 100 = 60%

girls (2/5) *100 = 40%

METHOD 2

5 - 100

2 ?

5---100

3 ?

EG:

IN A CLASS BOYS AND GIRLS ARE IN THE RATIO 3:2 then find percentage of boys

boys what percentage more that girls?

(1/2) * 100 = 50%

EG:

IN A CLASS BOYS AND GIRLS ARE IN THE RATIO 3:2 then find percentage of boys

girls what percentage more than boys ?

(1/3)* 100 = 33(1/3)%

EG:

IN A CLASS BOYS AND GIRLS ARE IN THE RATIO 3:2 then find percentage of boys

Boys is what percentage of girls?

(3/2)100 = 150%

EG:

IN A CLASS BOYS AND GIRLS ARE IN THE RATIO 3:2 then find percentage of boys

girls is what percentage of Boys ?

(2/5)*100 = 200/3 = 66(2/3) %

MODEL :

EG:

A Salary is 20 % less than b salary then b salary is what % more than a salary?

4 : 5

(1/4) 100 = 25%

short cut formulae

(X/(100±X))*100%

MORE - PLUS

DECREASE OR LESS -- MINUS

COMPARE ABOVE PROBLEM

(20/(100-20))*100

(20/80)*100 = 25%

EG:

A rectangle length increased by 10 % by what percentage breadth has to be decrease sothat no change in its area?

(10/(100+10))*100

(10/110)*100

9(1/11)%

EG:

price of a article decreased by 30% by what percentage it sales has to be increase so that these is no effect in revenue?

(30/70)*100

300/7

42(6/7)%

EG:

price of a sugar increased by 20% by what percentage it consumption has to be decreased sothat there is no change

(20/120)*100%

16(2/3)%

MODEL:

EG:

Population of a town is 5000 in the first year it is increased by 10 % and then 2nd year it decreased by 20 % find the

find the population after 2 years and the overall percentage

population first year 10% increased so 110/100

population second year 20% decreased 80/100

5000 *(110/100) * (80/100)

550*8

4400

(600/5000)*100

12% decreased

METHOD 2:

+10% -20%

ONLY ON TWO PERCENTAGE CHANGES ONLY

((X+Y+(XY/100)) %

(10-20-200/100)%

-12% DECREASED

EG:

A rectangle length is decreased by 10% and bredth decreased by 10 %

find the effect on its area?

(-10-20+(200/100)%

-28% decrease

EG:

thrice of a article first increased by 10% and again increased by 20 % then decrease by 25 %?

100*(110/100)* (75/100)

99%

1 percentage decreased

MODEL 3:

EG:

population of a town first increased by 10 %and then decreased by 205 if the final population is 4400 initial population?

increased by 10% so 100/110

decreased by 20% so 100/80

4400*(100/110)*(100/80)

5000

EG:

A man spends 85% of his income per household items and out of the remaining 50% per transport if he finally saves 900 find his income?

900*(100/15)*(100/50)

12500

EG:

In a college 30% are arts graduates out of the remaining 40% are science graduates out of the remaining 50% are computer

graduates find total no of students?

-30% -40% -50%

210*(100/70)*(100/60)*(100/50)

EG:

The ratio between a ,b,c is 3 :4 :5 a increased by 20% and b increased by 25% and c reduced by 10% then find new ratio?

300 : 400 : 500

360 : 400 : 500

36 : 50 :45

EG:

Total votes polled in a election is 1200 votes difference between the winning and loosing candidate is 20%

then find how much votes that winning candidate got?

100%

20% 80%

differcnce 60% = 1200

1% = 20 votes

80% = 1600 votes

EG:

IN A ELECTION BETWEEN TWO CANDIDATES ONE CANDIDATE GOT 60% VOTES AND WON BY 500 VOTES THEN FIND TOTAL VOTES?

100%

40% 60%

DIFFERENCE 20% = 500

1% = 25 VOTES

TORAL = 100*25 = 2500 VOTES

EG:

TO pass in an exam every guy need 40% marks but one candidate got 40 marks and then failed by 40 marks then

total marks in that exam?

pass : 40 + 40

80

so pass percentage 40% = 80marks

1% = 2 marks

100% = 200 marks

EG:

to pass in an exam students need 30 % marks but one student got 100 marks

he got 10 marks more than pass mark then total marks in that exam?

pass % pass marks

30% 100marks - 10 marks

30% 90 marks

1% 3 marks

100% = 300 marks

Eg

in an exam a got 32% marks and failed by 9 marks

b got 40% marks and pass by 15 marks then find total marks in that exam?

a 32% -9marks

b 40% 15 marks

difference 15-(-9)

24

8% 24 marks

1% ?

1 percent 3 marks

total marks 300

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