Decrease Percent

When a quantity shrinks (gets smaller), then we can compute its Decrease Percent:

                      ( Original amount - New amount)
Decrease %= ----------------------------------- x 100
                              Original amount

Note: When you compute percent decrease, you always compare how much a quantity has changed to the original amount.

Examples :

1) Find the decrease % of a) $80 to $60 b) $155 to $130

a) $80 to $60
Solution :
Original amount= $80
Net amount = $60
                      ( Original amount - New amount)
Decrease %= ----------------------------------- x 100
                              Original amount

       ( 80 - 60)
Decrease %= ------------ x 100
80

= (20/80) x 100

= 0.25 x 100

So, Decrease % = 25

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b) $155 to $130
Solution :
Original amount= $155
Net amount = $130
                      ( Original amount - New amount)
Decrease %= ----------------------------------- x 100
                              Original amount

        (155 - 130)
Decrease %= ------------ x 100
155

= (25/155) x 100

= 0.16129 x 100

So, Decrease % = 16.129

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2) On Sunday 845 people went to the Zoo. On Monday only 169 people went. What is the per cent decrease in the people visiting the Zoo on Monday?

Solution :
Original amount = 845

New amount = 169

                      ( Original amount - New amount)
Decrease %= ----------------------------------- x 100
                              Original amount

         ( 845 -169)
Decrease %= --------------- x 100
845

= (676/845) x 100

= 0.8 x 100

So, Decrease % = 80

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3) A man got 10% decrease in purchasing a machine . If the new price of the machine was $3000, find the original price of the machine.

Solution :
Decrease % = 10

New amount = $3000

Let original amount be $p.

                      ( Original amount - New amount)
Decrease %= ----------------------------------- x 100
                              Original amount

       ( p - 3000)
10 % = ---------------------- x 100
p

Cross multiply

10p = (p - 3000) x 100

10p = 100p - 300,000

10p-100p = -300,000

-90p = - 300,000

So, p = 300,000/90 p = $3333.33



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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