Throughput accounting

Was on this Forum before i left off late I just finished my f4 exam and was happy about it, hopefully I'm going to excel in it. I started studying for f5 yesterday and throughput accounting calculation part is giving me issues. I Don't really like Management accounting even in college also and i did f2(acca) i got 52% in it. I'm scared but i know i can excel if others did and passed it. I'm Currently Using my sister's Bpp2011(Don't Know if it outdated) and Revision kit Kaplan 2014 & Opentuition Lectures also Please Help me with these Question.- Example pg 54 Growler manufactures computer components . Health and safety regulations mean that one of its processes can only be operated 8 hours a day. The hourly capacity of this process is 500 units per hour.The selling price of each components is $100 and the unit material cost is $40. The daily total of all factory costs is $144, 000 excluding materials. Expected production is 3600 units per day. My Question is why did they use 1/500 I know is Time per unit but why did they use 1 to Divide 500 Please Help me Not really a Guru in Math and it confusing me Thank You