A woman bought 100 Christmas cards. For the ones that sing a song when you open them, she paid 30 cents each. For the rest she paid 5 cents each. If the cards cost $10.25 in all, how many of the expensive kind did she buy?

.05c+.3s=10.25, c+s=100, c=100-s (c is for cards that don't sing and s is for those that do :P)

.05c+.3s=10.25 and c=100-s makes the equation become:

.05(100-s)+.3s=10.25

5-.05s+.3s=10.25

.25s=5.25

s=21, and since c=100-s

c=79

So she bought 21 of the more expensive singing cards...

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ewomazinoade ewomazinoade · Answer 2 · 2022-03-22T11:57:55+01:00

The number of expensive cards bought is 80.

What are the linear expressions that represent the question?

a + b = 100 equation 1

0.3a + 0.05b = $10.25 equation 2

Where:

a = number of expensive cards bought

b = umber of inexpensive cards bought

How many expensive cards were bought?

Multiply equation 1 by 0.05

0.05a + 0.05b = 5 equation 3

Subtract equation 3 from 2

0.25a = 20

Divide both sides by 0.25

a = 80

To learn more about simultaneous equations, please check: https://brainly.com/question/25875552