The system of equations given during Claire's linear algebra aptitude test is: x+2y+3w+4z=10 2x-y+w-z=1 3x+y+4w+3z=11 -2x+6y+4w+10z=18(However Clare's comment, "Is this a joke?", is pertinent. It is indeed a joke. A solution is simple and ridiculous: x = y = w = z = 1. However, it is not the only solution. For example, x=2.4, y=3.8, w=z=0 is also a solution. The complete solution could be written as: x=2.4-s-.4t y=3.8-s-1.8t w=s z=t For all real values of s, t.