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

Question

I don't even know where to begin with this Q.

Answer 1

let the number of 20 cent stamps be x
then the number of 33 cent stamps is 50-x

solve:
20x + 33(50-x) = 1260

Answer 2

After solving the equation i get 3.9=x
??? isnt there a way you can solve it by letting x= number of postcard stamps and then y= number of letter stamps?

Answer 3

sure:
number of postcards stamps x
number of letter stamps y

x + y = 50
20x + 33y = 1260

from the first:: y = 50-x
then in the second

20x + 33(50-x) = 1260

well, look at that! I had that in the first line.

solution:
20x + 1650 - 33x = 1260
-13x = -390
x = 30
then y = 50-x = 50-30 = 20

(how did you get a decimal??? of 3.9x ? )

Answer 4

THANK YOU!!!!!! sorry! i feel like a waste of time for you, but im just not that smart ;)

Answer 5

number of postcards stamps x
number of letter stamps y

x + y = 50
20x + 33y = 1
20x + 1650 - 33x = 1260
-13x = -390
x = 30
then y = 50-x = 50-30 = 20

Answer 6

How do you set this as a matrix equation?