DMN12 — Table 47 should specify duration/duration rather than number/duration

Table 47 gives specific semantics of multiplication and division for various types of operands. It gives a row for division of a number by a duration (e.g. 4 divided by 1 hour) which makes little sense. Instead, the case of dividing a duration by a duration (e.g. 1 hour divided by 15 minutes equals 4) should be specified.

change table 47 to remove number/duration and add duration/duration

Apply editing instructions in Revised Text.