Problem

The key insight is that a converging lens can form real images of two different objects at the same location if you position it so that light from both sources converges to a single point. You'll need to use the lens equation $\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$ twice—once for each source—and exploit the constraint that both images coincide. The trick is recognizing that the two object distances must be different (since the sources are at different positions), but they produce the same image distance $v$, which gives you two equations to solve simultaneously.

The key insight is that a converging lens can form real images of two different objects at the same location if you position it so that light from both sources converges to a single point. You'll need to use the lens equation $\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$ twice—once for each source—and exploit the constraint that both images coincide. The trick is recognizing that the two object distances must be different (since the sources are at different positions), but they produce the same image distance $v$, which gives you two equations to solve simultaneously.