Aptitude - DATA Interpretation

To effectively tackle data interpretation questions, one has to develop the skill of gathering information from raw data. Read everything about the data - the title, units, footnotes, etc. While reading the questions, take appropriate pauses, and refer back to the data presented in table or graph. Do not just read the question at one go and then refer to the data. Reading forth and back is necessary to get a hold on relevant data and solve such questions.

Before you proceed revise the below formula(es):

PROFIT / LOSS / DISCOUNT:

Profit percentage(P%) = (Profit /Cost Price) × 100

Loss percentage(L%) = (Loss / Cost price) × 100

S.P. = {(100 + P%)/100} × CP(if SP > CP)

S.P. = {(100 – L%)/100} × CP(if SP < CP)

C.P. = {100/(100 + P%)} × SP(if SP > CP)

C.P. = {100/(100 – L%)} × SP(if SP < CP)

Discount = Marked Price – Selling Price

Discount Percentage = (Discount/Marked price) x 100

Total increase in price due to two subsequent increases of X% and Y% =  ((X + Y + XY)/ 100) %

If two items are sold at same price, each at Rs. x, one at a profit of P% and other at a loss of P% then there will be overall loss of P^2/100 %. 
The absolute value of loss = 2x * P^2 /(100^2-P^2)

SIMPLE INTEREST / COMPOUND INTEREST:

SI Formula, S.I. = Principal × Rate × Time

CI Formula, C.I. = Principal x (1 + Rate)^Time − Principal

RATIO and PROPORTION:

If	a	=	c	, then	a + b	=	c + d	.     [componendo and dividendo]
	b		d		a - b		c - d

If two numbers are in a:b ratio and the sum of these numbers is x, then numbers will be ax/(a+b) and bx/(a+b) respectively.

If the ratio of two numbers is a:b, then the number that should be subtracted from each of the numbers in order to make this ratio c:d is given by (bc-ad)/(c-d).

If a>b, then the ratio (a+x) : (b+x) is less than a : b

If a<b, then the ratio (a+x) : (b+x) is greater than a : b

If a=b, then the ratio (a+x) : (b+x) = a : b = 1

If x is a negative number, then the above inequalities get reversed.