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Help! Need by 10:30 to turn in and I'm confused!

When Anthony contracted the flu, he needed tissues and cough drops. Each box of tissues cost $1.69 and each bag of cough drops cost $1.19. By the time he was well again, he had gone through a combined 13 boxes of tissues and bags of cough drops, and he had spent $19.47. How many boxes of tissues did he use? How many bags of cough drops?

User ThreeFx
by
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1 Answer

5 votes

Answer:

8 boxes of tissues

5 bags of cough drops

Explanation:

You need to write a system of equations.

x = number of tissue boxes

y = number of cough drop bags

x (number of tissue boxes) + y (number of cough drop bags) = 13 (total number of tissues and cough drops combined.

So, your first equation is

x + y = 13

Then, you need to write the second equation.

(1.69 [cost of 1 tissue box] * [number of tissue boxes]) + (1.19 [cost of one bag of cough drops] * [number of cough drop bags] = 19.47 [total cost of tissues and cough drops]

That's a lot to read, so here's the equation simplified!

1.69x + 1.19y = 19.47

Now, you have two equations:

x + y = 13

1.69x + 1.19y = 19.47

I would solve with the substitution method.

the first equation can be changed to x = 13 - y by subtracting y from both sides.

Then, your two equations are:

x = 13 - y

1.69x + 1.19y = 19.47

Now, you can plug in that value of x into the second equation!

1.69(13 - y) + 1.19y = 19.47

21.97 - 1.69y + 1.19y = 19.47

subtract 21.97 from both sides

-1.69y + 1.19y = -2.5

Add the y values

-0.5y = -2.5

divide both sides by -0.5

so, y equals 5 bags of cough drops

now that you know what y equals, plug it back into your original equation to find x!

x + y = 13

plug in y

x + 5 = 13

x = 8

so, x = 8 boxes of tissues

Hope this helps! Let me know if you have any questions!

User Leo Prince
by
5.8k points
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