Mathematics and Stastics

 RELATIVE SPEEED AND TRAIN QUESTIONS Speed has no sense of direction unlike the velocity. Relative speed is the speed of one object as observed from another moving object. Questions on train are the classic examples of relative speed and in all these questions it is assumed that trains move parallel … Read more

 Prepositions Prepositions are short words (on, in, to) that usually stand in front of nouns (sometimes also in front of gerund verbs). Even advanced learners of English find prepositions difficult, as a 1:1 translation is usually not possible. One preposition in your native language might have several translations depending on the situation. The … Read more

     Surds A surd is a square root which cannot be reduced to a rational number. For example,  is not a surd. However  is a surd. If you use a calculator, you will see that  and we will need to round the answer correct to a few decimal places. This makes it less accurate. If … Read more

 Concepts of geometry Points, Lines & Planes   The most fundamental geometric form is a point. It is represented as a dot with a capital alphabet which is its name. A line is a set of points and it extends in opposite directions up to infinity. It is represented by two points on … Read more

 Fractions Any unit can be divided into any numbers of equal parts, one or more of this parts is called fraction of that unit. e.g. one-forth (1/4), one-third (1/3), three-seventh (3/7) etc. The lower part indicates the number of equal parts into which the unit is divided, is called denominator. The upper part, which indicates the number … Read more

 Median Median is the middle number in a sorted list of numbers. To determine the median value in a sequence of numbers, the numbers must first be arranged in value order from lowest to highest. If there is an odd amount of numbers, the median value is the number that is in the … Read more

 Contribution of aryabhatta in mathematics Number notation Numerical values He made a notation system in which digits are denoted with the help of alphabet numerals e.g., 1 = ka, 2 = Kha, etc. Aryabhatta assigned numerical values to the 33 consonants of the Indian alphabet to represent 1,2,3…25,30,40,50,60,70,80,90,100. Notation system  He invented a … Read more

 Change of binary number to decimal number and decimal number to binary number Binary Number System Digital computer represents all kinds of data and information in the binary system. Binary Number System consists of two digits 0 and 1. Its base is 2. Each digit or bit in binary number system can be … Read more

 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

 Number system 1. Basic Formulae  (a + b)(a – b) = (a2 – b2) (a + b)2 = (a2 + b2 + 2ab) (a – b)2 = (a2 + b2 – 2ab) (a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca) (a3 + b3) = (a + b)(a2 – ab + b2) (a3 – b3) = (a – b)(a2 + ab + b2) (a3 + b3 + c3 – 3abc) = (a + b + c)(a2 + b2 + c2 – ab – bc – ac) When a + b + c = 0, then a3 + b3 + c3 = 3abc   2. Types of Numbers I. Natural Numbers Counting numbers 1,2,3,4,5,…1,2,3,4,5,… are called natural numbers   … Read more