SOLUTION: An 80% decrease followed by a 100% increase is the same as a 50% decrease followed by what other percent decrease?Please explain

Algebra ->  Percentages: Solvers, Trainers, Word Problems and pie charts -> SOLUTION: An 80% decrease followed by a 100% increase is the same as a 50% decrease followed by what other percent decrease?Please explain      Log On


   



Question 558832: An 80% decrease followed by a 100% increase is the same as a 50% decrease followed by what other percent decrease?Please explain
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
If you start with 100, an 80% decrease brings you down to 100-80=20.
A 100% increase is an increase by the same amount, so 20 turns into 20+20=40.
On the other hand if the same starting 100 was decreased by 50% to 100-50=50, to get to a final number of 40 you have to subtract another 10=50-40. As a percentage of the previous 50, the subtracted 10 constitutes a 20% decrease
10%2F50=percentdecrease%2F100 ---> percentdecrease=%2810%2F50%29%2A100=10%2A100%2F50=20
You could use x instead of percentdecrease to give it a little algebra flavor.
A lot of complicated algebra flavoring could be added, but it's not needed, so I'll let it be.