latest percentages simple shortcut material

 

 latest material on percentages 

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

50% = 50/100 = 1/2
1/2 = 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