First, the unit is words per minute, not the other way round because you're interested in how fast people can type, not how much time passes for every number of words they write or read (that would be minutes per word)
now, we know they do 4200 in 60 minutes.
we need to divide 4200 by 60- first,

so the answer is, 70 words per minute
I think you made a typo in your answer and you meant 4600 instead of 4200 - then the answer is <span>C. 76 2/3 word/min</span>
You think about the junk while doing the junk to answer the junk.
i hope i helped (;
The right answer is E. Sodium (with 140mmol/L)
Sodium is the most important element in the blood and extracellular liquids of the body.The needs of an adult subject are of the order of 1 to 2 g of sodium per day. The normal diet is much richer than our actual needs, about 4g, so it can largely compensate for the needs of an athlete or a runner.
Losses are majoritarly by feces and sweat. The kidney is able to reabsorb almost all the sodium that is filtered: urinary losses can be tiny.