A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
To add to what rich007a has said, in case your number is already entered as 7.32 in A1 you may use the following formula in B1 to convert it into a time.
=TIME(0,INT(A1),MOD(A1,1)*100)
You need to change the formatting to m:ss or [m]:ss as suggested.