Wherever Statements | Index |

This problem uses the following rate equation:

rate X time = effort

However, in addition, a sum equation is required. That is, Mary's rate and Sam's rate must be added to get the combined rate. This "sum equation" pertains to the rows, not the columns like in previous equations. Thus a two dimensional chart is needed to accommodate all of the facts.

-------------------------------- | | rate| time |effort| -------------------------------- | Mary | m | | | | + ---------------------- | Sam | s | | | | = ---------------------- | combined| m+s | | | --------------------------------