Hey

I am trying to figure out how to do a formula using Log 20. I have figured out how to do it using log10. But no Log20

The equation i need to work out is the following...

SRI = 20Log(fm)-47

f=frequency
m=mass

so the actual equation is:

20log(63*17)-47

I know the answer is 13.595789 but cannot get Excel to arrive at this answer.

Can anyone help?

Thank You

John