Mathematics and Stastics

Chain Rule

 CHAIN RULE This module will teach you the basics of direct and indirect proportions. These concepts will further help you in time and work questions. Important Formulas – chain rule Direct Proportion Two quantities are said to be directly proportional, if on the increase or decrease of … Read more

Pipe And Cistern

 Pipes and Cistern   Inlet: A pipe connected with a tank or a cistern or a reservoir, that fills it, is known as an inlet.   Outlet: A pipe connected with a tank or cistern or reservoir, emptying it, is known as an outlet.   If a pipe can fill a tank in x hours, … Read more

Discounts

 Discount   The discount is referred to the reduction in the price of some commodity or service. It may anywhere appear in the distribution channel in the form of modifications in marked price (printed on the item) or in retail price (set by retailer usually by pasting a sticker on the item) or in list price (quoted for the buyer). The discount … Read more

Time And Distance And Intrest

 Time and distance Relationship between speed, distance and time Speed = Distance / Time or Distance = Speed × Time Average Speed = 2xy / x+y where x km/hr is a speed for certain distance and y km/hr is a speed at for same distance covered. As we know, Speed = Distance/ Time. … Read more

Boat And Stream

 BOAT AND STREAM Boat and stream problems is a sub-set of time, speed and distance type questions where in relative speed takes the foremost role. We always find several questions related to the above concept in SSC common graduate level exam as well as in bank PO exam. Upon listing … Read more

Age Problems

 Age Problems   Important Formulas on “Problems on Ages”:   1. If the current age is x, then n times the age is nx. 2. If the current age is x, then age n years later/hence = x + n. 3. If the current age is x, then age n years ago = x – n. 4. The ages in a ratio a : b will be ax and bx. 5. If the current age is x, … Read more

Relation Between Arc Radius And Angle

 Relation between arc radius and angle     Arc length   =   [radius • central angle (radians)] Arc length   =   circumference • [central angle (degrees) ÷ 360]     Proof of the trigonometric ratios of complementary allied angles Two acute angles are complementary to each other if their sum is equal to 90°. In … Read more

Time & Work

 TIME AND WORK In these problems the number of persons, quantity of work done and time taken are important factors. Also time taken by a person depends on the efficiency of that person which comes into picture when different people do the work such as women, children do the work … Read more

Pie

 Pie-chart A pie graph (or pie chart) is a specialized graph used in statistics. The independent variable is plotted around a circle in either a clockwise direction or a counterclockwise direction.The dependent variable (usually a percentage) is rendered as an arc whose measure is proportional to the magnitude of the quantity.Each arc is … Read more