Flour, eggs, yeast, and salt are mixed by weight in the ratio of 11 :

If we just mixed the number of pounds in the ratio provided, we'd have 11 pounds of flour + 9 pounds of eggs + 3 pounds of yeast + 2 pounds of salt for a total of 25 pounds in the mixture.

That's close, but not quite the 20 pounds we wanted. 20 pounds is pretty close to 25, so we don't need to decrease the 3 pounds of yeast by much. Answer choices A and B are wrong, as they would have us decreasing each ingredient by more than 50%. Answer choice E is wrong, as it has us adding even more yeast. Answer choices C and D appear to be pretty close, but C would require us to reduce the mixture by \(\frac{1}{3}\) and 20 is definitely more than \(\frac{2}{3}\) of 25, so answer choice C is wrong.

And we are left with answer choice D.



That SHOULD be all the explanation you need, since getting good at ballparking is a huge asset on the GMAT. But if you REALLY want to solve out the rest of the problem, fine.

We want a total that is \(\frac{20}{25}\) of the 25 pound mixture, or 80%. That means we need to cut each ingredient amount by 20%. The question asks for the number of pounds of yeast, so we want 80% of the 3 pounds we had in the 25 pound mixture. 80% of 3 = 2.4

Answer choice D.