1. First, convert the model distance to base SI.

Then the ratio of model distance to actual distance is

or 1 : 5 × 10¹¹.
2. The model/actual distance ratio should be the same for each planet.
Mercury:


or 1 : 4.6 × 10¹¹.
Venus:


or 1 : 5 × 10¹¹.
Mercury's distance is the incorrect one. The correct model distance should be
such that

Solve for
.




3.The actual distance for Mars is
such that

Solve for
.




4. Divide the distance by the speed of light to recover the time.

Convert to minutes.
