Question 46252
Simplify:
{{{(5-(a/b))/(15/b)}}}
Simplify the numerator first:

{{{5-(a/b) = (5b-a)/b}}} You get this by putting the fractions over a common denominator, then subtracting.  The common denominator is b.  The second fraction is already over b so don't change it.
To get the first fraction over b you multiply the 5 by {{{b/b}}} to get {{{5b/b}}}. Now you have both parts over the common denominator of b and you can subtract.
{{{5-(a/b) = (5b-a)/b}}} 

So now you have:
{{{((5b-a)/b)/(15/b)}}}

Remember, to divide two fractions, you copy the first, flip the sign from divide to multiply, and flip (invert) the second fraction. So it now becomes:
{{{((5b-a)/b)*(b/15)}}} Cancel the b's
{{{(5b-a)/15}}}...and this is as far as you can go!