One year ago a window washing service charged $100 for setup and an additional $30 per hour for on-site washing. This year the company charges $20 for setup and an additional $50 per hour for on-site washing. Which of the following is equivalent to the percentage change from last year to this year that the company charges for setup and x hours of on-site washing?
-
A100{(3x+10)/(2x-8)}%
-
B200{(x-4)/(3x+10)}%
-
C200{(x-4)/(5x+2)}%
-
D200{(4-x)/(3x+10)}%
-
E200{(4-x)/(5x+2)}%
显示答案
正确答案: B