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)
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)
what to do in the case when first increases then decreases and then again increases.
जवाब देंहटाएंFirst deal with any two and then deal with resultant and third one...
हटाएंWhat would be the ans if area of circle decreases by 36%? Then how much area decrease?
जवाब देंहटाएंValue of pie is constant..take r and r instead of x and y in the above formula
जवाब देंहटाएं