Spelling mistakes in a text are either “nonword errors” or “word errors.” A nonword error produces a string of letters that is not a word, such as “the” typed as “teh.” Word errors produce the wrong word, such as “loose” typed as “lose.” Nonword errors make up 25% of all errors. A human proofreader will catch 80% of nonword errors and 50% of word errors.
Reference: Ref 12-4

Of all the errors that the proofreader catches, what percent are word errors?

A. 3.48%
B. 37.5%
C. 57.5%
D. 65.2%

Question

Spelling mistakes in a text are either “nonword errors” or “word errors.” A nonword error produces a string of letters that is not a word, such as “the” typed as “teh.” Word errors produce the wrong word, such as “loose” typed as “lose.” Nonword errors make up 25% of all errors. A human proofreader will catch 80% of nonword errors and 50% of word errors.
Reference: Ref 12-4

Of all the errors that the proofreader catches, what percent are word errors?
	
A.	3.48%
B.	37.5%
C.	57.5%
D.	65.2%

anonymous · Answer

lets use a good trick, make up some numbers

anonymous · Answer

i think i screwed that up. the wording is very confusing let me try again
lets say there are 2000 errors, 25% are non word so 500 non word and the rest, 1500 word

anonymous · Answer

80% of 500 is 400 so 400 non word errors
50% of 1750 is 875 so 875 word errors are caught

anonymous · Answer

ok

anonymous · Answer

the total number of errors caught is 400 + 875 = 1275

anonymous · Answer

of those, 875 are word errors, so compute the percent 
$$\frac{875}{1275}$$

anonymous · Answer

i get 68%  so either i made another mistake, or the answer is not in your list

anonymous · Answer

yeah i made a mistake
50% of 1500  is 750 and 750 + 400 = 1150

anonymous · Answer

$\frac{750}{1150}=65.2\%$ rounded

anonymous · Answer

sorry i messed up before
making up numbers when you are not given them is a good gimmick to use
you can do it with decimals, but this way is usually easier