Quantitative Aptitude Study Notes for Bank & SSC
Exam
MATH PERCENTAGE % SHORTCUT TRICKS
You know that quantitative
aptitude section is most important in bank
exams in PO and Clerk and for
other competitive exams because if you want good score in bank exam then you
have to score good in maths. In competitive exams the most important thing is
time management, if you know how to manage your time then you can do well in Bank Exams. That’s where maths shortcut
tricks and formula are comes into action.
The one of the most important
topic in maths is Percentage %. You should know how to calculate maths percentage in very short time. For this here we are
providing shortcut tricks to calculate percentage in maths.
The term percent means ‘for every
hundred’. It can best be defined as:
“A fraction whose denominator is
100 is called a percentage (%), and the numerator of the fraction is called the
rate per cent”.
The example given below will
illustrate the percents and their fractional value.
Ex. A woman
invests 9% of his income into shares. It means:
i.
She invests Rs. 9 out of every Rs. 100 of her income into shares.
ii.
She invests 9/100 of her income into shares.
Now, if her income is 10000, how
does she invest in shares?
Your answer should be 10000*9/100; =900Rs.
Some important or most used prime fractions for maths percentages:
Percent
|
Decimal
|
Fraction
|
1%
|
0.01
|
1/100
|
5%
|
0.05
|
1/20
|
10%
|
0.1
|
1/10
|
12½%
|
0.125
|
1/8
|
20%
|
0.2
|
1/5
|
25%
|
0.25
|
1/4
|
331/3%
|
0.333...
|
1/3
|
50%
|
0.5
|
1/2
|
75%
|
0.75
|
3/4
|
80%
|
0.8
|
4/5
|
90%
|
0.9
|
9/10
|
99%
|
0.99
|
99/100
|
100%
|
1
|
|
125%
|
1.25
|
5/4
|
150%
|
1.5
|
3/2
|
200%
|
2
|
|
Examples with shortcut tricks on how to calculate percentages are given below:
Ex: Find 8% percent of Rs. 625.
Solution:
8% of Rs 625 = 2/25 × 625; = Rs 50.
Ex: what fraction is 25/2 % percent?
Solution:
25/200; =1/8
Ex: What percentage is equivalent to 3/8?
Solution:
3/8 × 100; = 75/2 = 371/2%
Ex: Ram’s salary is increased from Rs 630 to Rs700. Find
the increase percent.
Solution:
Increase in salary = Rs700-Rs630 = Rs70
Percentage
increase = 70/630 × 100; = 111/9%
To calculate how much percent one quantity is of another.
Ex: Express
the fraction which Rs. 1.25 is of Rs. 10 as a percentage.
Solution: fraction = 1.25/10;
= 125/1000; = 1/8
Then; 1/8= 100/8 /100
= 121/2%
Ex: 12% of a certain sum of money is Rs.43.5. Find the
sum.
Solution: 12/100 of a sum= Rs 431/2%
The sum = 87/2 × 100/12
= Rs. 362.50
Ex: Two
numbers are respectively 20% and 50% more than the third. What percentage is
the first of the second?
Solution: we will use theorem for
this question:
Theorem1: if two values are respectively x% and Y% more
than a third value, then the first is the 100+x/100+y × 100% of the second.
So by using this formula we will
solve the question:
=120/150 × 100 = 80%
Theorem 2. If A is x% of C and B is Y% of C, then A is
x/y × 100% of B.
Ex: Two
numbers are respectively 20% and 25% of a third number.
Solution: following the above
theorem, we have the required value.
=20/25 × 100
=80%
Ex: A
positive number is divided by 5 instead of being multiplied by 5. What % is the
result of the required correct value?
Solution: Let the no. be 1, then
the correct answer = 5
The incorrect answer that was
obtained = 1/5
The reqd. % = 1×100% / 5×5
= 4%
here also study the other maths notes, click on the link given below;
here also study the other maths notes, click on the link given below;
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