47% of the students in a class of 42 students has glasses or contacts. How many students in the class have either glasses or contacts? Choose one
A) 15 B) 16 C) 17 D) 18 E) 20
a=r⋅b   47%=0.47a   =0.47⋅42   a≈20   Option 20 is correct.
<result>E</result>
47% of the students in a class of 42 students has glasses or contacts. How many students in the class have either glasses or contacts?