Question

Postcard stamps are 20¢ each, while letter stamps are 33¢ each. If you have 50 stamps worth $12.60, how many of each type do you have?

Answer 1

You have 30 postcard stamps and 20 letter stamps.

Explanation:

To solve this you'll need to set up a system of equations. Let's use P for postcard stamps and L for letter stamps

Remember, since the price is in cents, it'll be 0.2 and 0.33.

The equations can be in any order, this is just the order I chose.

0.2P + 0.33L = 12.60

P + L = 50

Your next step is to cancel out one of the variables to solve for the other. Let's cancel out P and solve for L. (You can switch these if you want, you'll still get the same answsrs.) Remember to multiply by a negative so the variable cancels out.

Here's what your work will look like:

0.2P + 0.33L = 12.60

-0.2(P + L = 50)

Here's what your new equations will look like after distributing:

0.2P + 0.33L = 12.60

-0.2P - 0.2L = -10

Now add these two equations together. When you do so, the P cancels out, and you can now solve for L.

Here's what your new equation will look like after adding the two equations:

0.13L = 2.6

Now, divide both sides by 0.13 to get what L equals. After doing so, you should get L = 20. This means that you have 20 letter stamps.

Your last step is to plug the value of L (which is 20) into either of your original equations to solve for how many postcard stamps you have. Let's use our second equation, P + L = 50. (You can use either original equation and get the same answer, but this one is more simpler to use.)

Here's what your work will look like:

P + 20 = 50

Subtract 20 from both sides:

P = 30. This means you have 30 postcard stamps.

Hope this helps!

Answer 2

Answer: 50 total stamps = 30 Postcard Stamps + 20 Letter Stamps

Explanation:

Postcard Stamp = Ps

Letter Stamp = Ls

Ps = 20c

Ls = 33c

50 total stamps = $12.60

50 total stamps = X Ps + Y Ls

12.60 = 30 Ps + 20 Ls

$12.60 = 30(20c) + 20(33c)

50 total stamps = 30 Postcard Stamps + 20 Letter Stamps