Your question is Two-Scale Heavier Sphere. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You have a balance scale and 9 metal spheres. One of the spheres is slightly heavier than the other 8, which are of equal weight. How can you identify the heavier sphere using the scale only two times?