Bunuel wrote:

A carton contains 30 pens, of which 20 are blue ink pens and 10 are black ink pens. If 9 of the pens are removed, what is the new ratio of blue ink pens to black?

(1) Of the pens removed, the ratio of the number of black ink pens removed to the number of blue ink pens is 2 : 1.

(2) Of the first 7 pens that are removed, 5 are black.

(1) Of the pens removed, the ratio of the number of black ink pens removed to the number of blue ink pens is 2 : 1.If removed ratio is \(black:blue=2x:1x\) (where x is a multiplier), then \(2x+x=9\), and \(x=9/3=3\).

So, removed ratio is \(black:blue=2x:1x=6:3\) and new ratio \(blue:black=20-6:10-3=14:7\); sufficient.

(2) Of the first 7 pens that are removed, 5 are black. So out of 9 we know that 5 are black and 2 are blue, but we don't know the remaining 2; insufficient.

(A) is the answer.