Ok lets look from the beginning.

the problem can be translated to the following eqn
C + 12 = 2R
=> C = 2R - 12 ---------(1)
Question is: Is C < R ?

stmt 1: R > 5
coz tapes cant be fractions, R is +ve integer.

R can be any integer starting from 6 upto infinity.

start plugging numbers for R
R = 6. C = 2*6 -12 = 0
So R = 6, C = 0
Yes C < R.

start plugging others numbers..
at R = 12, C = 12.
No C not < R.

Any value of R > 12 will make C > R.

So stmt 1 Insufficient.

Since u know about stmt 2, I wouldnt explain.
Actually my explanation of stmt 1 already answers stmt 2.

HT helps

Thank you much vittalgmat! However, I just wanted to clarify a little typo that threw me off a bit. When you equate the problem and come up with eqn: c+12=2R, you then factorize c as c=2R=12, but it should be c=2R-12, sholdn't it? The rest is chrystal clear. Thanks a lot!

Rodrigo wrote:Thank you much vittalgmat! However, I just wanted to clarify a little typo that threw me off a bit. When you equate the problem and come up with eqn: c+12=2R, you then factorize c as c=2R=12, but it should be c=2R-12, sholdn't it? The rest is chrystal clear. Thanks a lot!

Thanks Rodrigo for pointing it out.
I have made the correction.
so (1) now reads
C = 2R - 12.