Featured Original PDF
Featured Original PDF
PERCENTAGE IMPORTANT FACTS AND FORMULAE Concept of Percentage : By a certain percent ,we mean that many hundredths. Thus x percent means x hundredths, written as x%. To express x% as a fraction : We have , x% = x/100. Thus, 20% =20/100 =1/5; 48% =48/100 =12/25, etc. To express a/b as a percent : […]
SURDS AND INDICES I IMPORTANT FACTS AND FORMULAE I LAWS OF INDICES: am x an = am + n am / an = am-n (am)n = amn (ab)n = anbn ( a/ b )n = ( an / bn ) a0 = 1 SURDS: Let a be a rational number and n […]
PROBLEMS ON AGES Ex. 1. Rajeev’s age after 15 years will be 5 times his age 5 years back. What is the present age of Rajeev ? (Hotel Management,2002) Sol. Let Rajeev’s present age be x years. Then, Rajeev’s age after 15 years = (x + 15) years. Rajeev’s age […]
PROBLEMS ON NUMBERS In this section, questions involving a set of numbers are put in the form of a puzzle. You have to analyze the given conditions, assume the unknown numbers and form equations accordingly, which on solving yield the unknown numbers. SOLVED EXAMPLES Ex.1. A number is as much greater than 36 as is […]
SQUARE ROOTS AND CUBE ROOTS IMPORTANT FACTS AND FORMULAE Square Root: If x2 = y, we say that the square root of y is x and we write, √y = x. Thus, √4 = 2, √9 = 3, √196 = 14. Cube Root: The cube root of a given number x is the number whose […]
SIMPLIFICATION IMPORTANT CONCEPTS ’BODMAS’Rule: This rule depicts the correct sequence in which the operations are to be executed,so as to find out the value of a given expression. Here, ‘B’ stands for ’bracket’ ,’O’for ‘of’ , ‘D’ for’ division’ and ‘M’ for ‘multiplication’, ‘A’ for ‘addition’ and ‘S’ for ‘subtraction’. Thus, in simplifying an expression, […]
DECIMAL FRACTIONS IMPORTANT FACTS AND FORMULAE Decimal Fractions : Fractions in which denominators are powers of 10 are known as decimal fractions. Thus ,1/10=1 tenth=.1;1/100=1 hundredth =.01; 99/100=99 hundreths=.99;7/1000=7 thousandths=.007,etc Conversion of a Decimal Into Vulgar Fraction : Put 1 in the denominator under the decimal point and annex with it as many […]
H.C.F. AND L.C.M. OF NUMBERS IMPORTANT FACTS AND FORMULAE Factors and Multiples : If a number a divides another number b exactly, we say that a is a factor of b. In this case, b is called a multiple of a. Highest Common Factor (H.C.F.) or Greatest Common Measure (G.C.M.) or Greatest Common Divisor (G.C.D.): […]