Thursday, 12 March 2015

PERCENTAGE

When we think about the percentage come in mind is 100 the century :) not the Cricket batsman scored.

It's real account number Helped to calculate your Shares,interest,profits,....

Take 100

100% of 100=100
50% of 100=50
25% of 100=25
10% of 100=10
5% of 100=5 It's quiet easy , not like that.

Take 12

100%=12
50%=6
25%=3
10%=1.2
5%=0.6

TRICKS:

100% of x=x
50% of x=x / 2
25% of x=x / 4
10% of x= x / 10=Put dot after single digit from right to left . Eg:250's 10%=25.0=25
5% of x=10%of x / 2
1% of x=Put dot after two digit from right to left.1%=2.50=2.5
When we try to solve the question they are asking for 98%=90%+5%+3% (OR)10%*9+5%+1%*3


QUESTION AND ANSWER

Number of girls in a class is 44 wich is 55% of the total number of students.How many boys are there in the class?

44=55% then 100%=?
55%=44
100%=?(Take % one side values another side here % left side(55%,100%) values right side(44,?))
100%*44 / 55%(cross multiplication of purple marked)
(100/100)*44))/ (55/100)
44*(100/100)*(100/55)
(44*100)/55
4400/55
80=100%
80-44 Girls=36 Boys

80% of 135 +? % of 750=228

(80/100)*135+(x/100)*750=228
(x/100)*750=228-108
(x/100)*750=120(How many % of 750 is 120)
100%=750
?%=120
Cross multiply here
(750*?%) / (120*100%)
750*(x/100) / 120*(100/100)
  15 x=240
x=240/15=16%

(OR)

80%=8*10%
8*13.5=80+24+4.0=108

x% of 750=228-108
x% of 750=120
10%of 750=75+45(more then 50% of 75)
10%+5 and above %=16% Approximately.





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