Multiply 2 field by a number and each other

I have a form that I would like a formula for. The scenario is:

Security guards are booked 1:50 at $35 an hour. I would like to put the number of hours into field 35_X and then put the number of guards into field X. I would then like for the following to calculate into field Total_6:

(35_X * $35)*X

So, # of hours * rate ($35) * # of guards

Please help!

Thanks,

Jessica