Answer
200%
Work Step by Step
old price is .20
new price is 1.20
old price index is 150
new price index is 300
Old price (indexed to today's pricing):
$.20*(300/150)$
$.2*2=.4$
Change in price:
$(1.2-.4)/.4$
$.8/.4$
$2$
The change in price is 2, and since this is a number (not a percent), we multiply this by 100 to get a rate of 200 percent.
