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#1 2007-08-20 12:48:35

allbasha
Member
Registered: 2007-08-20
Posts: 2

adding % and deducting from help me

hello all

small problem ask by my child

if caluclating %   like

300*80%=540   ok

now  minus the 80% from the figure how can we get actual figure?

A=  ?
B=80%

A*80%=1006.2

WHAT IS TE VALUE OF  A?


help me

basha

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#2 2007-08-20 13:41:01

mikau
Member
Registered: 2005-08-22
Posts: 1,504

Re: adding % and deducting from help me

we have that 80% of A is 1006.2 

this means that 80*A/100 = 1006.2

so 80A = 100620

and A = 100620/80.


A logarithm is just a misspelled algorithm.

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#3 2007-08-20 17:59:40

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,711

Re: adding % and deducting from help me

Read Percentages, Percentage Difference and try Percentage Calculator (it has explanations behind the calculations)


"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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#4 2007-08-20 21:35:25

allbasha
Member
Registered: 2007-08-20
Posts: 2

Re: adding % and deducting from help me

mikau wrote:

we have that 80% of A is 1006.2 

this means that 80*A/100 = 1006.2

so 80A = 100620

and A = 100620/80.

hello mikau

sorry your quote not match

just we need to bring back the princple figure by deducting 80% of the total  figure

here  A=?

A*80% =1006.2  so we need common formula to bring back the A value

one time we can figur out  but when ever the values changes  the formula must be correct to caluclate

thanks for your post  i hope some one will help me to find out

basha

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