计算 percentage increase from initial (old) 值 to final (new) value:
计算 final (new) 值 from initial (old) value and percentage increase:
The percentage increase/decrease from initial 值 (Vinitial) to final 值 (Vfinal) is equal to the initial and final values difference divided by the initial 值 times 100%:
Price percentage increase from initial 值 of $1000 to final value of $1200 is caluclated by:
Price percentage increase from initial 值 of $1000 to final value of $800 is caluclated by:
So
percentage decrease = 20%
The difference d is equal to the initial 值 Vinitial times the percentage increase/decrease p divided by 100:
The final 值 Vfinal is equal to the initial 值 Vinitial plus the difference d:
Vfinal = Vinitial + d