Percentage

12/27/13 MBA|CAT|CAT 2013|CAT 2014|CAT Online|MBA 2013|MBA 2014|MBA Entrance Exams|CAT Test|Preparation|CAT Questions

totalgadha.com/mod/forum/discuss.php?d=110 1/6

our competence with percentages and its application should form a very important part of your armory of CAT2010 preparation or, for that matter, preparation for any other MBA exam. The concept of percentage will beapplied in not only your quant section but also your data interpretation (DI) section. Therefore, master thisimportant concept and make it your habit to calculate percentages mentally.

The word "percentage" litera lly means "per hundred" or "for every hundred." Therefore, whenever youcalculate something as a part of 100, that part is numerically termed as percentage.

In other words, percentage is a ratio whose second term is equal to 100. For example, 1:4 can be written as25: 100 or 25%, 3: 8 can be written as 37.5: 100 or 37.5%, 3: 2 can be written as 150: 100 or 150%, and soon.

IMPORTANT CONCEPTS ASSOCIATED WITH PERCENTAGE

Basic formula of percentage:

Percentage of:

Percentage increase/decrease:

Percentage increase/decrease when a quantity a increase/decreases to become another quantity b is

Percentage less than/greater than:

Have a look at the picture given below:



You can see that Johnny is taller than Vicky. What will your answer be if I ask

(a) By what percentage is Johnny taller than Vicky?

(b) By what percentage is Vicky shorter than Johnny?

Answer:



Therefore, to find the final quantity after a 20% increase, we can directly multiply the old quantity by a factorof 1.2 and get the new quantity. Similarly, for a 20% decrease, we can multiply the old quantity by 0.8 andget the new quantity. The factors to be multiplied for var ious percentage increase/decrease are given below:



The biggest advantage of using the factors is that for subsequent percentage increase/decrease, we just keepon multiplying the corresponding factors and get the final quantity.

Example:

1. The performance bonus of a sa lesman increases by 10% in the first year, by 20% in the second year, andby 30% in the third year. What is the overa ll percentage increase in his bonus in 3 years?

Answers: Let the bonus at the start of the first year be Rs100.

Therefore, to find the final bonus we just multiply by factors.

Final bonus = 100 1.1 1.2 1.3 = 171.6.

Therefore, overall percentage increase = 71.6%

NOTE: note that taking initial va lue of 100 makes the problem simpler; whatever increase we get is directlyequal to the percentage increase.

2. An amount was first reduced by 10% and then further reduced by 20% and Rs10 800 were left. What wasthe original amount?

Answer: Let the or igina l amount be A.

Therefore A 0.9 (factor for 10% decrease) 0.8 (factor for 20% decrease) = 10 800

Or A = Rs15 000.

SOME SOLVED EXAMPLES



I shall have to end here and leave the rest of it for my CBT Club students. I shall cover someproblems based on this in the CBT Club this week.

Percentage

Documents

Transcript of Percentage