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Wherever Statements Index

Two Dimentional Tables

Consider the following problem:
Example 7: Mary does a job in 6 days while Sam does it in 8 days. How long does it take them to do the job together?
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 |       |      |
Often, the operators (i.e. "+" and "=") are not used in the table, just as the are often not used in the table header. The work together problem (Example 7) illustrates how to set up the tables. Wherever statements are used in Class II problems.