multiply-dayTimeDuration(xdt:dayTimeDuration("PT2H10M"), 2.1)
from within a Java application, in order to extract the result from the result sequence, one would have to use this code:
String n = ((XDTDayTimeDuration)rs.first()).stringvalue(); println(n);
which returns a xdt:dayTimeDuration value corresponding to 4 hours and 33 minutes ‘PT4H33M’