Time and Work.. Using rate as a tool Updated On 5/26/2015 |
Problem 1 Difficulty: hard 1. The grass on a ranch grows at a constant rate every week. 240 cows will eat up the grass in 6 weeks. 200 cows will eat up the grass in 10 weeks. For how many weeks can the pasture sustain a herd of 190 c...
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Permutation and Combination demystified Updated On 5/26/2015 |
Problem 1 There are 3 similar boxes, containing 6 black and 4 white balls; 3 black and 7 white balls and 5 black and 5 white balls respectively. If you choose one of the three boxes at random and from that particular box pick up a black ball at rand...
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Math tip 34 Updated On 10/15/2013 |
Geometry A quadrilateral with all four vertices on the circle is called a cyclic quadrilateral. For a cyclic quadrilateral the sum of opposite angles =180° In a circle, the radius is always perpendicular to the tangent.
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Math tip 33 Updated On 10/15/2013 |
Geometry In a circle, angle subtended by diameter at the centre = 180° and angle subtended by diameter at a point which lies on the circumference = 90°. In a circle, angle subtended by chord at centre is double the angle subtended by the chord at its vertex.
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Math tip 32 Updated On 10/15/2013 |
Geometry In a circle, the perpendicular line joining the centre and the chord bisects the chord. In a circle, chords which are equidistant from the centre and are equal in length, subtend the same angle at the centre.
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Math tip 31 Updated On 10/15/2013 |
Geometry In a triangle, if the sides are not equal, the greater side has a greater angle opposite to it, the smaller side has a smaller angle opposite to it.
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Math tip 30 Updated On 10/15/2013 |
Co-ordinate geometry Line of intersection of two planes is a line. Line of intersection of two vertical planes is a vertical line or an oblique line. Line of intersection of a horizontal plane and vertical plane is a horizontal line.
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Math tip 29 Updated On 10/15/2013 |
When an inequality has |x| take a value of x > 0 and a value of –x > 0, to plot the graph
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Math tip 28 Updated On 10/15/2013 |
Inequalities To solve problems based on inequalities, draw a xy graph. Determine the relevant region under observation. By determining the position of the origin the relevant region can be plotted.
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Math tip 27 Updated On 9/13/2013 |
To solve a sum dealing with number of men and number of days taken to complete a work use the logic: 1 person takes 1 day to complete 1 unit of work. If 20 men take 20 days to complete a work, How many days it will take 40 men take?
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Math tip 26 Updated On 9/10/2013 |
To convert meters/sec into kilometer per hour. Multiply the speed by 18/5
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Math tip 25 Updated On 9/10/2013 |
To convert kilometer per hour into meters/sec. Multiply the speed by 5/18
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Math tip 24 Updated On 9/10/2013 |
Effective speed If two bodies are moving in the same direction, effective speed = sum of their speeds
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Math tip 23 Updated On 9/10/2013 |
Effective speed If two bodies are moving towards each other, effective speed = difference of their speeds.
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Math tip 22 Updated On 9/10/2013 |
Relative speed If two bodies are moving in the same direction, Relative velocity = Difference of their speeds.
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Math tip 21 Updated On 9/10/2013 |
Relative speed If two bodies are moving towards each other, Relative velocity = sum of the their speeds.
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Math tip 19 Updated On 9/10/2013 |
Steps to solve a Time-Speed-Distance problem Draw a line diagram:(representation of the variables, positions and relationships) Check units:(All units should conform to each other) Find constant parameter Write equation
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Math tip 18 Updated On 9/10/2013 |
Mixtures In a mixture containing two inseparable liquids, use this formula to compute the percentage of each liquid after replacing the liquid with the larger percentage with the liquid with smaller percentage n times. (initial amount of liquid) x { (initial amount of liquid...
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Math tip 17 Updated On 9/10/2013 |
Alligations When different quantities of same or different ingredients of different values are mixed together to produce a mixture of a mean value, use alligation. Rule of alligation { Quantity of cheaper ingredient/ Quantity of Dearer ingred...
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Math tip 16 Updated On 9/5/2013 |
if a/b is such that (a/b)<1 then {(a-x)/(b-x)} < (a/b)
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Math tip 15 Updated On 9/5/2013 |
if a/b is such that (a/b)<1 then {(a+x)/(b+x)} > (a/b)
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Math tip 14 Updated On 9/5/2013 |
if a/b is such that (a/b)>1 then {(a-x)/(b-x)} > (a/b)
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Math tip 13 Updated On 9/5/2013 |
if a/b is such that (a/b)>1 then {(a+x)/(b+x)} < (a/b)
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Math tip 12 Updated On 9/5/2013 |
If a:b = 3:4 then a and b are not equal to 3 and 4 respectively. a = 3x and b = 4x where x is any constant. (a,b) can be (15,20),(18,24),(3,4), (30,40)...
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Math tip 11 Updated On 9/5/2013 |
compound interest(nth year) = compound interest((n-1)th year) + r% x compound interest((n-1)th year) Amount(nth year) = Amount((n-1)th year) + r% x Amount((n-1)th year)
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Math tip 10 Updated On 9/5/2013 |
Compund interest after 2 years - simple interest after 2 year = principle x (rate /100) ^2
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Math tip 9 Updated On 9/5/2013 |
simple interest after 1 year = compound interest after 1 year
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Math tip 8 Updated On 9/5/2013 |
Working backwards an excelleng problem solving approach
The owner of a jewellery shop hired three watchman to guard his diamonds, but a thief still got in and stole some diamonds. On the way out, the thief met each watchman,one at a time. to each he gave ½ of the diamon...
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Math tip 7 Updated On 9/5/2013 |
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Number S is obtained by squaring the sum of digits of a two-digit number D. if difference between S and D is 36, then the two-digit number D is a. 54 b. 36Know more...
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Math tip 6 Updated On 8/21/2013 |
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Adding two percentage a% + b% doesn't give (a + b) %, it gives Know more...
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Math tip 5 Updated On 8/21/2013 |
1^2=1 2^2= 1+3 Know more...
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Math tip 4 Updated On 8/21/2013 |
Sum of numbers of 3^0, 3^1, 3^2 and 3^3 will be 40. Using a combination of these numbers, each occurring at the most once, we can obtain all numbers from 1 to 40 by using the operatio...
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Math tip 3 Updated On 8/21/2013 |
The sum of powers of 2 from 0 to any number K will be equal to 2^(K+1) – 1
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Math tip 2 Updated On 8/21/2013 |
If a is increased/decreased by b%, then the new value calculated after the increase is, Know more...
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Math tip 1 Updated On 8/21/2013 |
When the word 'lesser than' or the word 'more than' is used in the question, the percentage increase formula must be used. The number after the word 'than' is usually the initial valu...
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