How to subtract 2 dates in oracle to get the result in hour and minute

Question

I want to subtract 2 dates and represent the result in hour and minute in one decimal figure.

I have the following table and I am doing it in this way but the result

Answer 1

Try this

round(to_number(end_time - start_time) * 24)

Answer 2

try this:

    SELECT
    TRIM(TO_CHAR(TRUNC(((86400*(end_time - start_time))/60)/60)-24*(trunc((((86400*(end_time - start_time))/60)/60)/24)),'00')) ||'.'||
    TRIM(TO_CHAR(TRUNC((86400*(end_time - start_time))/60)-60*(trunc(((86400*(end_time - start_time))/60)/60)),'00')) ||'.'  as duration
FROM come_leav;