选择题
2007 AMC 8 Problem 6: Long-Distance Call Cost Decrease
The average cost of a long-distance call in the USA in 1985 was 41 cents per minute, and the average cost of a long-distance call in the USA in 2005 was 7 cents per minute. Find the approximate percent decrease in the cost per minute of a long-distance call.
A.
7
B.
17
C.
34
D.
41
E.
80