1. The problem statement, all variables and given/known data A point P (x,y) is moving along the line y=(1/2)x. If x is decreasing at the rate of 3units/s, at wha rate is the distance between P and the fixed point Q (0,11) changing at the instant when P is at (6,3)? 2. Relevant equations Implicit differentation 3. The attempt at a solution From what I can see for this question, the distance formula needs to be used. That is what I did, I plugged in the point (x,y) and (0,11) into the distance formula and found the derivative, then plugged in (6,3) for x and y and -3 for dx/dt. The answer I got was -2.6, however, this is not the right answer as it is supposed to be -0.6. This question seems easy yet it is frustrating me, if anyone could be help it would be greatly appreciated, thank you.