The question is "For single women in the poll, the percentage who said no exceeded the combined percentages for those who said yes and those who said not sure by 22%. If the percentage who said yes is doubled, it is 7% more than the percentage who said no. Find the percentage of single women who responded yes, no, and not sure." The chapter deals with matrices so I naturally tried to setup the problem as follows 1 1 -1 | -22 (yes, no, not sure) 2 0 -1 | 7 The back of the book setups on an equations as follows x + z = y - 22 2x = y + 7 I tried to eliminate one of the variables, but then I always end up with two unknowns in the final equation. The main problem I'm running into is that the chapter provides examples that Gaussian Elimination works nicely on, but this method does not appear to work so nicely on this problem. Is the way I setup it up the first time correct & is there a particular method that would work better than another to solve the problem? Fyi, the back of the book as yes 34%, no 61%, & not sure 5% for the answer.