A toy factory manufactures d dolls every hour. Each doll costs c cents. How many dollars will the factory spend in costs for manufacturing dolls in 7 hours and 30 minutes?
A. 3cd/40
B. 7cd/100
C. cd/750
D. 15cd/100
E. cd/100
Manufacturing Cost = (d dolls/hour) (c cents/doll)
= cd cents/hour = cd/100 $/hr.
Now, 7 hours and 30 minutes = 7 1/2 hours = 15/2 hours.
Total Manufacturing Cost = (cd/100 $/hr) (15/2 hr) = 15cd/200 $ = 3cd/40 $.