Hi houd,

In answer to your original question, the prompt asks us to figure out the following fraction:

(Day Crew Boxes Loaded)/(ALL Boxes Loaded)

You determined that the Night Crew loaded 3/5 as many boxes as the Day Crew, so if the Night Crew = 3/5, then the Day Crew = 5/5 = 1.

The TOTAL boxes loaded by both crews is 3/5 + 1 = 8/5.
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This is actually a perfect question to use TEST VALUES.

We're told that each night crew worker loaded 3/4 as many boxes as each day crew worker:

Let's TEST VALUES:
1 day crew worker = 4 boxes loaded
1 night crew worker = 3 boxes loaded

The night crew has 4/5 as many workers as the day crew:

Day crew = 5 workers
Night crew = 4 workers

So, we have....
Day crew: 5 workers who load 4 boxes each = 20 boxes loaded
Night crew: 4 workers who load 3 boxes each = 12 boxes loaded

The question asks, what fraction of ALL BOXES did the DAY CREW LOAD:

20/32 = 5/8

Final Answer: E