text: Dude, tell your math teacher he/she is a moron.  This is not a good question.  I majored in Chemical Engineering at college.  I've done more math than your teacher could ever imagine, and I've got to tell you that this question has absolutely no meaning in the real world.  Why?  Because you can't predict how she would work alone based on the information given.  What if she works extra hard when she's around Rick, but slacks off when she's alone.  You can't tell, so the problem is useless.\n\nThat said, here's the answer a moron math teacher (who doesn't really have what it takes to do math in the real world) would want to see:\n\nG + R = -6 (negative because they spent hours.)\nR = -15 (negative because he spent 15 hours.)\n\nplug in R\n\nG + (-15) = -6\n\nG = -6 + 15\n\nG = 9 hours (positive because that's the time she saved Rick when she helped him.  Saved hours are positive)\n\nThus, if you were a moron (like your math teacher) you could assume that it would take G 9 hours to do it alone, but like I said before that's just plain STUPID.