The market value of a certain machine decr
题型：单项选择题
问题：
The market value of a certain machine decreased by 30 percent of its purchase price each year. If the machine was purchased in 1982 for its market value of $8,000, what was its market value two years later ？（）
A．$8,000
B．$5,600
C．$3,200
D．$2,400
E．$800