the highest percentage for deaths in construction from highest to lowest is as follows: falls, struck by objects, electrocution, and caught-in/between. these four are collectively known as fatal four.
in the case of falls, the type that is responsible for the overall highest death in the category is falls from roofs.
i don't see any
your answer is a
ending amount = beginning amount / (2^n)
where "n" = number of half-lives (or elapsed time / half-life)
ending amount = 50 mg / (2 ^10 / 5.3)
ending amount = 50 mg / (2 ^ 1.8867924528)
ending amount = 50 m / 3.6981210597
ending amount = 13.5203794557 mg
or about 13.5 mg remain