Formula Required

[EugeneRequilet]

I need a maths formula to calculate amount to charge to allow for a 10% discount.
e.g. I need to find a value that after I have taken the discount of 10% to be 1000.
You cant just add 10% on because that comes to 1100 and 10% discount on 1100 is 110. So the amount in this case is 990. I need the end result to 1000.
A = P( 1 + i )n does not work.

 

[BigBeachBanana]

$$X(1-10\%)=1000\\ X=\frac{1000}{1-10\%}=1111.11$$In general,
$$X=\frac{A}{1-r}$$where A is the desired discounted amount, X is the charge amount, r is the discount rate.

 

[Deleted member 4993]

I need a maths formula to calculate amount to charge to allow for a 10% discount.
e.g. I need to find a value that after I have taken the discount of 10% to be 1000.
You cant just add 10% on because that comes to 1100 and 10% discount on 1100 is 110. So the amount in this case is 990. I need the end result to 1000.
A = P( 1 + i )n does not work.

From the response above (#2), you can see that

A = P * ( 1 + i ) * n

does work. However, the variables (A, P, i & n) need to be re-interpreted according to new situation. Please learn the process of deriving that equation, and you will be able to use it in many places with modifications.

 

[EugeneRequilet]

$$X(1-10\%)=1000\\ X=\frac{1000}{1-10\%}=1111.11$$In general,
$$X=\frac{A}{1-r}$$where A is the desired discounted amount, X is the charge amount, r is the discount rate.

Thanks a lot, this works perfectly.