Answer: 90%
Explanation:
Cycle Service Level refers to the expected probability by which a manufacturer meets the demand for a particular product and is not being stockout.
In this case,
40% of the days, 80 are sold;
50% of the days, 90 are sold
10% of the days; 100 are sold.
Since the vendor plans to stock 90 each day, then the vendor will meet demand during 40% of the days, when 80 are sold; and during 50% of the days, when 90 are sold.
Therefore, the expected CSL is the vendor targeting will be:
= 40% + 50%
= 90%