Increase Percent
When a quantity grows (gets bigger), then we can compute its Increase Percent:
( New amount - Original amount)
Increase Percent= ------------------------------- x 100
Original amount
|
Note: When you compute percent increase
you always compare how much a quantity has changed to the original amount.
The numerator in these formulas is always a POSITIVE number
(or zero, if the quantity doesn't change at all).
Examples :
1) The size of a bag that could hold 5 kg of sugar has now been increased so that it can hold 6kg. What is the percentage increase in size?
Solution :
Old Capacity of the bag = 5 kg
New capacity of the bag = 6 kg.
( New amount - Original amount)
Increase Percent= ------------------------------- x 100
Original amount
|
∴ Increase % = [( 6 – 5 ) / 5] x 100
= ( 1 / 5) x 100
= 20 %
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2) The salary of a bank clerk was increased by 7%. If his present salary is $8,025. What was it before increment?
Solution :
Let the salary before increment be ‘a’ .
( New amount - Original amount)
Increase Percent= ------------------------------- x 100
Original amount
|
7 = [( 8025 – a )/ a ] x 100
7 x a = ( 8025 – a ) x 100 [ cross multiply ]
7a = 802,500 – 100 a
∴ 7a + 100a = 802,500
107a = 802,500
∴ a = 802,500 / 107
Salary before increment = $7500.
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3) Your friend diets and goes from 125 pounds to 200 pounds. What was her percentage weight gain?
Solution :
Original weight = 125 pounds
New weight = 200 pounds
As the weight increase so here we use increase % formula.
( Original amount - New amount)
Increase Percent= ------------------------------- x 100
Original amount
|
Decrease % = [( 200 - 125)/ 125 ]x 100
= (75 / 125 ) x 100
= (3/5) x 100
= 300 /5
= 60 %
So, she gained her weight by 60 %.
Percentage
• Conversion of Percentage to Fraction
• Conversion of Fraction to Percent
• Conversion of Percentage to Decimal
• Conversion of Decimal to Percent
• Find the Percentage of a given number
• What Percent is one number of another number
• Percentage as a comparison of two quantities
• Increase Percent
• Decrease Percent
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