The normal production rate for a certain machine that runs continuously was n units per day. Over a period of 10 days, the machine was shut down part of the time for cleaning and servicing, but produced at the normal rate when in operation. If the machine's total production during this period was 60% of its normal production, then the total time that the machine was shut down was equivalent to how many days?
(A) 0
(B) 1
(C) 2
(D)4
(E) 6
(A) 0
(B) 1
(C) 2
(D)4
(E) 6
