How would I solve this problem?

You don't need your math book. Just get a pencil and paper and maybe a calculator and try out different numbers until you get the answer.

15 of the 39 and 10 of the 37

Let:

f represent the 39 cent stamp

and

s represent the 37 cent stamp

f + s = 25

.39f + .37s = 9.55

25 - s = f

.39(25 - s) + .37s = 9.55

9.75 - .39s + .37s = 9.55

.2 = .02s

10 = s

f = 25 - 10 = 15

15 of the 39 cent stamps and 10 of the 37 cent stamps

Just work it out, you could multiply .39 by 25 to see how high that would bring it and then determine how many would actually be .37 cent stamps by lowering the total price by .02 for every stamp.

15 stamps were bought at 39 cents

10 stamps were bought at 37 cents

too easy

x 39¢ stamps, y 37¢ stamps

x + y = 25 and therefore x = 25 - y

39x + 37y = 955......substitute for x

975 - 39y + 37y = 955

2y = 20

y = 10

x = 15

You need to use a linear system, and you should start with 'let' statements.

Ex. Let x represent the amount of 39 cent stamps.

Let y represent the amount of 37 cent stamps.

From there, you need to create your equations.

x + y = 25

0.39x + 0.37y = 9.55

Using those equations, solve the system (through substitution or elimination methods) and you should have your answer.

Good luck!

9.55=0.39y+ 0.37X

25= y+x

And then combine the equation

9.55=0.39y+0.037x

-9.25=-0.39y-0.037x

------------------------------

0.3=0.02y+0

y= 0.3/0.02 = 15

so 25=15+x

x=25-15

x=10

so it mean she buy 15 stamps were bought at 39 cents &10 stamps were bought at 37 cents

hope u understand it now

By opening your math book.

By looking into your math book, or asking your parents.

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