dollars/cents multiplied by hours/minutes or tenths

[JiggsTiger]

I am using a worksheet that has this formula in merged cells Q & R:
=sum(42.15*(S15+T15/10)), in column S the number is a whole number 0 to 40
and in column T the number is 5 (for 30 minutes) or 3 (2.5 for 15 minutes) or
8 (7.5 for 45 minutes). I can have only one numeral in column T.
How can I stop the rounding up?
I have tried using the precision option but then the total does match what I
have on the original invoice. I need the merged columns Q/R to total up to
what I enter on a adding machine (which is off by 3 or 4 cents).
Is it possible to attach the worksheet I am using so that what I am trying
to write is more understandable?

 

[Jerry W. Lewis]

A function is not required to do arithmetic, just a formula preceded by =.
Thus your formula can be simplified to
=42.15*(S15+T15/10)

Your question is not clear. I tried several of your proposed values for
S15:T15, and the result always seems correct.

Attachments to newsgroups are strongly discouraged, and because of filters
will greatly reduce the number of people who see your post, and therefore
reduce your chances of getting an answer. Instead, give a specific example
of values for S15:T15 that cause the problem, then note what you are actually
getting vs. what you think you should be getting.

Jerry