Hi David,
Numbers for iOS is one of the topics in the iWork for iOS community. It's understandably difficult to find as Apple has never really packaged or promoted Numbers, Pages and Keynote as components of an iWork package in the iOS versions.
Your question is about formulas, though, so the answer should be pretty much the same with regard to the functions to use.
You ask how you can 'set that cell to yield the answer in "time" vs a "number". "Time" in Numbers refers to 'time of day', and is always part of a Date & Time value that specifies a certain instant in time. Which is not what you want to use. The amount of time that has passed is a Duration, measured in weeks, days, hours, minutes, seconds and milliseconds.
For your example, you state "A five gallon bucket has a hole that leaks one gal per hr Minute."
Assuming "hr" got in there accidentally, and the flow rate is 1 gal./min., your setup and formula could look like this:
B2: 5
B3: 1
B4: =DURATION(,,,B2/B3)
If it's a small hole, and the flow rate is actually 1 gal./hr., the only difference would be in B4:
B4: =DURATION(,,B2/B3)
In either formula, Numbers for Mac will replace "/" with the division sign, "÷"; Numbers for iOS will, I think, have you enter the ÷ directly.
You will be able to format the cell to show durations in a variety of formats, and will be able to choose which units to display.
Syntax for the DURATION function is: DURATION(weeks,days,hours,minutes,seconds.milliseconds)
As seen in the example, the leading commas are needed to tell DURATION what unit to start with.
Regards,
Barry