Please see the attachment.sairamGmat wrote:. Is 5^k less than 1,000 ?
(1) 5^ (k-1) >3000
(2) 5^(k-1) = 5^k - 500
Official Answer is B
Can any one explain why is this so?
5^k > 15,000 or 15,000 < 5^k only gives us the that 5^k cannot exceed 15,000 but can we not say that 5^k < ___. So it only gives us the upper range not the lower one. 15,000 < 5^k < ___________ How can we fill in this blank?gmat1011 wrote:In stem 1 if 5 to the power k >15000 then doesnt it imply that 5^k is certainly NOT less than 1,000 (its a number in excess of 15,000) --- so it is sufficient to answer the question and so D?
But if thats the case stem 1 and stem 2 would be providing different answers with respect to the possible value of 5^k (GMAT questions do not have contradictory stems)...
But 1 does look sufficient on its terms to me. Rahul@gurome can you please explain? Thanks for your time.
Hi Rahul,Rahul@gurome wrote: 5^k > 15,000 or 15,000 < 5^k only gives us the that 5^k cannot exceed 15,000 but can we not say that 5^k < ___. So it only gives us the upper range not the lower one. 15,000 < 5^k < ___________ How can we fill in this blank?
Does this help?
You are right, (1) is SUFFICIENT here. Thanks for pointing that out!kvcpk wrote:
Hi Rahul,
You are missing something.
5^k>15000 means that 5^k>1000
We dont need to check again what 5^k is less than.
it might be like this: 15000<5^k<25000
But we are really not concerned with the upper limit.
Lower limit is 15000 which is greater than 1000.
You just got confused for once I believe.I know your credibility on this forum though.
