Percent means ' out of hundred ' or a fraction in which denominator is 100. If we say 50% then it means 50 /100 .
To express a fraction ( a / b ) as percentage , then multiply by 100.
(a/b) * 100 = (a/b)% e.g (1/5) * 100 = 20% .
Some of common percentage into fraction .
Percentage table:
1/2 - 50 %
1/3 - 33(1/3) %
1/4 - 25 %
1/5 - 20 %
1/6 - 16(2/3) %
1/7 - 14(2/7) %
1/8 - 12(1/2) %
1/9 - 11(1/9) %
1/10 - 10%
1/15 - 6(2/3) %
1/20 - 5 %
1/25 - 4 %
1/50 - 2%
1/100 - 1%
CASE I:
1.If the salary of A is X% more than B, then by what %, B's salary is less than A?
Ans: To solve find the percentage which is less than X%.
For eg. if X% is 20%(=1/5), the find a fraction less than 1/5 ,i.e 1/6. = 16 (2/3) % - ans.
2. If the salary of A is X% less than B, then by what %, B's salary is more than A?
Ans: In this , find the percentage which is more than X%.
For eg. if X% is 20%, the find a fraction more than 1/5, i.e 1/4 = 25%
CASE II:
1. If you find a question :
(i). Add x% of a number to a given number A. Find the number?
(ii). What % has to be added to A to get B?
(iii) Adding x% to a number gives B, what is the number?
Ans: To solve this , the formula is " A+ x% of A = B "
2. A's salary is 20% more than B, by what % B's salary less than A?
Ans: By using pervious two concepts,
( x / ( 100 +/- x ) * 100 ) %
As we are asking to for a lower %, so denominator must be more (+).
(20 / 120 ) * 100 = 16(2/3) %
CASE III:
we genralize the concept, A% of B = C
If either two are given , we can find the other one.
______________________________________
Categories:
Aptitude
