Question

If 20% of all manually filed returns contain errors, and 0.05% of all electronically filed returns contain errors, how much more likely is a manual filer to make an error than an electronic filer?
a.
40,000 times more likely
b.
4,000 times more likely
c.
400 times more likely
d.
40 times more likely

Answer 1

20% = 0.20 and 0.05% = 0.0005.
0.20 ÷ 0.0005 = 400.

So a manual filer is 400 times more likely to make an error — answer (c).