IN 1972 it took 75.7 pounds of glass to produce one hundred 16-ounce glass bottles. In 1992 it took 48 pounds of glass to make the same number and size of bottles. What is the percent decrease in the number of pounds of glass used in 1972 compared with 1992 to produce one hundred 16-oz bottles?

this is what I did. Can someone verify if I did it right? Thanks.

percent change: (75.5-28)/ 75.7 = (.366) 100 = 37%

percent decrease: 1-.37= .63

75.7 (.63)=

ans: 47% decrease.