How to get the actual value after subtracting discount(%)

Question

I want to get the total amount with the help of Final amount and Discount rate.

For Example.

Grand total = 100

Discount = 15%

Final Amount =100*.15=85

if I have only two variables

Final amount = 85

Discount = 15%

Grand total = ?

Now I can get back Grand total with the help of "Final Amount" and "Discount rate"?

Answer 1

Let Grand Total = X

X-(X * 15 %) = 85 then if you find the value of X then your Grand total can e found.

X - 3X/20 = 85

17X= 85*20

X = (85/17)*20

X =100

Put it .. You will find the Grand Total

Answer 2

Let x = Grand Total.

We know that

100-100*0.15=85

Let's substitute 100 with X.

x-(x*0.15) = 85

then we can simply apply basic PEMDAS operation. So let's multiply

x-0.15x = 85

we know that the first x is = 1, so

1x-0.15x = 85

which equals to

0.85x=85

divide 0.85 on both sides to find X

0.85x/0.85 = 85/0.85 = 100