Question 1101909
To solve this problem, you have to set up a system of equations:

Let x be the $0.27 stamps and y be the $0.33 stamps

{{{x+y=24}}}
{{{.27x+.33y=6.84}}}

To solve this, you need to use substitution. Solve the first equation for y (y=24-x)and then substitute it for the y in the second equation.

{{{.27x+.33(24-x)=6.84}}}

Then, distribute the .33:

{{{.27x+7.92-.33x=6.84}}}

Then,combine the .27 and the .33:

{{{-.06x+7.92=6.84}}}

Then, subtract 7.92 from each side.

{{{-.06x=-1.08}}}

Then, divide by -.06 on each side.

{{{x=18}}}

X= 18, so there are 18 $0.27 stamps. Since there are 24 stamps total, you would subtract the 24 by 18 and get 6. There are 6 of the $0.33 stamps.

Answer: Sam sold 18 27 cent stamps and 6 33 cent stamps.