Find the elapsed time between 6:39 a.m. and 9:20 a.m.

Answer 1

This is a simple subtraction problem.   (Just remember to "borrow" correct amounts.)

    9  :  2  0  a.m.

  - 6  :  3  9  a.m.

-----------------------------

    9  :  1 60  a.m.

  - 6  :  3  9  a.m.

-----------------------------

                 51

    9  :  1 60  a.m.

  - 6  :  3  9  a.m.

-----------------------------

                 51

    8  : 61 60  a.m.

  - 6  :  3    9  a.m.

-----------------------------

    2  :  58    51

 2 hours 58 minutes and 51 seconds   = 2:58:51