help pwease i have midterm today!! =*(

Can someone please explain successive percentages to me.

Spot prices for crude oil are rather volatile. From 1998 to 1999, spot prices for crude oil decreased by 28%. From 1999 to 2000, they increased by 106%. What was the percentage change over the two year period from 1998 to 2000?

Question

help pwease i have midterm today!! =*(

Can someone please explain successive percentages to me.

Spot prices for crude oil are rather volatile.  From 1998 to 1999, spot prices for crude oil decreased by 28%.  From 1999 to 2000, they increased by 106%.  What was the percentage change over the two year period from 1998 to 2000?

phi · Answer

one way:   say you start with 100 in 1998
decrease by 28%:   100- 28% of 100= 100-28= 72
1998 100
1999   72
2000   increase by 106%    72+ 1.06*72= 148.32

can you find the total percent change from 1998 to 2000?
100+ 100*x% = 148.32

anonymous · Answer

oh im so lost... i don't know what step to take next

anonymous · Answer

is this the formula 
(New-Old)/Old = %
Old + % * Old = New or Old*(1+%)=New
Old = New
1 + %

phi · Answer

use (New-Old)/Old = % (actually this is a fraction. multiply by 100 to get percent) If this topic is a bit fuzzy, http://www.khanacademy.org/math/arithmetic/percents Get some popcorn and watch these.