Is 5^k less than 1,000?
(1) 5^(k-1) > 3000
(2) 5^(k-1) = 5^k - 500
(1) we get 5^k > 15000 ..clearly sufficient ....
(2) we get 5^k * 4/5 = 500 so.. 5^k = 2500/4 ..sufficient
weird question. we should get the same "Answer" with both?
That's not so weird of a question. This is not "advertised" but if you examine DS questions in the OG, you will NEVER find two answers that contradict each other. This is good to know for the GMAT because if you do find two answers that contradict each other, you did something wrong somewhere....
Former Senior Instructor, Manhattan GMAT and VeritasPrep
Vice President, Midtown NYC Investment Bank, Structured Finance IT
MFE, Haas School of Business, UC Berkeley, Class of 2005
MBA, Anderson School of Management, UCLA, Class of 1993