is strictly the percentage of the original amount??

original amount as 'x'. To find the increase or decrease, multiply the rate by the original amount 'x'. To find the final amount, add or subtract the increase or decrease to the original amount 'x' and equate this to given final amount. Solve the equation and find the original amount 'x'.

Step-by-step explanation:

sorry friend I don't have any answer but hope this example helps you ☺️

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!