Bunuel wrote:

Official Solution:

Question: \(x-y=?\)

(1) In one year Jules earned $24 more than Jim from bond M. \(0.12x-0.12y=24\). Reduce by 0.12: \(x-y=200\). Sufficient.

(2) If the interest were 20% then in one year Jules would have earned $40 more than Jim from bond M. Basically the same type of information as above: \(0.2x-0.2y=40\), reduce by 0.2: \(x-y=200\). Sufficient.

Important note: when two quantities are increased (decreased) by the same percent their difference also increase (decrease) by the same percent. For example if you increase 100 and 150 by 20% to 120 and 180 respectively, then their difference will also increase by the same 20% from 50 to 60.

Answer: D

Hi

Could you please confirm whether "earned" is just interest or orginal invested+interest?

Just in case if happened to problem solving.

In this DS it didnt matter though.