I am trying to do a calculation using difference between two hour:minute time
data in the following format.

A1 B1
02:50 03:00

When I subtract (B1-A1) I get an answer 0:10 and I can change this to 10 by
custom formatting the cell to [mm]

I want to use this value of 10 mins to divide a distance value to get
answers in ft/min format. e.g. 100 ft divided by 10 mins = 10 ft/min

But this is where my problem starts. I get some obscure high number as
excel reads 10 mins as 0.0069444.

Please help & advise. Many thanks in advance.