Question 27923
Call the original price of the jeans x. So 15% of the original price would be 15% times x or .15x.  So when we take the orginal price, subtract the discount (since it's "15% off) we get the equation:
{{{x-.15x=29.74}}}Combine x's
{{{.85x=29.74}}}Divide both sides by .85:
{{{x=34.99}}} $34.99 at 15% off ($5.25 discount) leaves us with $29.74 jeans. Check.

For problem 2, first let's get rid of the "other bills" and focus only on tens and twenties. Because he had $147 in other bills, and a total of $1167, that means the total from 10s and 20s must be 1167-147=$1020.
Lets call the number he has of each x. So he has x 10s and he has x 20s.  The value from the 10s is 10x (for instance if he had 7 tens the value would be 10*7=70). Likewise the value from the 20s is 20x. When we add the two values we get 10x+20x. Because we already figured that this sum must be $1,020 we can write:
{{{10x+20x=1020}}}Combining x's again:
{{{30x=1020}}}Divide:
{{{x=34}}}
So the teller had 34 tens ($340) and 34 twenties ($680) and the $147 in "other bills" for a grand total of $1167. Check.