(1) n < 0.1

Here if you take any value for n i.e less than 0.1 and greater than zero.
20% of n will always be very small as compared to 0.5

for example, say n = 0.02
Now 20% of 0.01 = 0.004

20% of any number number which is less than 0.1 will always give smaller number than 0.5

Suff

(2) n > 0.01

Consider the above ex which says
20 percent of n < 10 percent of the sum of n and 0.5

and take n = 10, then
20 percent of n > 10 percent of the sum of n and 0.5
(2 > 1.5)

Insuff

Choose(a)

Slighltly easier solution(IMO):



To find
if .2n > .1(.5+n)
.2n>.05+.1n

.1n > .05


Stmt I

n<1/10
Multiply both sides by .1
.1n < .01

Therefore .1n<.05

SUFF

Stmt II

n>.01
Multiply both sides by .1
.1n > .001 (DONT KNOW IF ITS GOING TO BE GREATER THAN .05 OR NOT)

INSUFF