SHORT TRICKS APPLIED IN PERCENTAGE :) 1. If the value of something is increased by x % and again increased by y % then resulting effect in percent Total change = {x+y+x*y/100} Example : The Salary of a worker is first increased by 10% and thereafter increased by 5%. What is the overall change in percent. Solution: overall change = + 10 + 5 + (+10)(+5)/100 = +15.5 % (increased) use (+) sign for increment and (-) sign for decrement. 2.If the value of something is increased by x % then decreased by y % then resulting effect in percent Total change = {+x- y+ (x*(-y)/100)} Example : The Salary of a worker is first increased by 10% and thereafter decreased by 5%. What is the overall change in percent. Solution: overall change = + 10 – 5 +(10)(-5)/100 = +4.5 % (increased) use (+) sign for increment and (-) sign for decrement. 3.If the value of something is decreased by x % and again decreased by y % then resulting effect in percent Total change = {-x – y + (-x)*(-y)/100} Example : The Salary of a worker is first decreased by 10% and thereafter decreased by 5%. What is the overall change in percent. Solution: overall change = – 10 – 5+ (-10)(-5)/100 = -14.5 % (decreased) use (+) sign for increment and (-) sign for decrement. Now, this is just the formula but its application are endless in the question of percentage , for the questions like 1. If both the lengths (%) and breadth(%) of a rectangle are changed find the change in area(%) ? 2. If the speed and time of a vehicle are changed, find the change in distance ? Similarly in all those questions where two quantities are multiplied to produce third one rate * time = cost efficiency * time = work average * no. of elements = total value rate * quantity = price (expenditure)
Posted on: Tue, 01 Jul 2014 02:55:32 +0000
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