During a Quality Control Test, the Nail Place Found That $\%$

Multiple Choice

During a quality control test, The Nail Place found that 10 nail guns were defective. This amount was 0.5 $\%$ of the nail guns tested.
a) How many nail guns were tested?
b) How many nail guns tested were not defective?

A) a) 2000; b) 1990
B) a) 20; b) 1990
C) a) 200; b) 1990
D) a) 2000; b) 2010
E) a) 20; b) 10