Question 276346
{{{log(200, (20))}}}
The change of base formula is: {{{log(a, (p)) = log(b, (p))/log(b, (a))}}}. We will use this to change the base 200 logarithm into an expression of a base our calculators "know" (like base 10 or base e (ln)). I'll use base 10:
{{{log((20))/log((200))}}}
I'll leave it up to you to find the two logarithms and then divide. (Do not try to reduce the fraction before you find the logarithms!)