How much fertilizer containing 30% nitrogen should be mixed with a fertilizer containing 10% nitrogen to get 10L of a fertilizer containing 12% nitrogen?

1L of 30% fertilizer and 9L of 10% fertilizer

Step-by-step explanation:

Let x = the amount of fertilizer containing 30% nitrogen.

Let y = the amount of fertilizer containing 10% nitrogen

x + y = 10 because the two fertilizers together will be 10L

0.3x will be the amount of nitrogen in the 30% nitrogen fertilizer, and 0.1y will be the amount of nitrogen in the 10% fertilizer. If you add those together, you will get 12% of the nitrogen in the 10L mixture. This makes this equation:

0.3x + 0.1y = 0.12(10)

0.3x + 0.1y = 1.2

Now we have our two equations.

x + y = 10

0.3x + 0.1y = 1.2

We can use substitution to solve this system of equations.

x = 10 - y

Substituting this into the second equation, we have:

0.3(10-y) + 0.1y = 1.2

3 - 0.3y + 0.1y = 1.2

3 - 0.2y = 1.2

1.8 = 0.2y

9 = y

10 - 9 = 1L

There will be 9L of 10% nitrogen fertilizer and 1L of 30% nitrogen fertilizer.

to find the unit price, we must figure out the cost of one item (in this case one dish towel).   to do this, we divide the total price ($7.92) by the number of items bought (for this problem it is 8, because there are eight dish towels in one pack).  

$7.92/8 = $0.99

therefore, the unit price, or the price of one dish towel, is $0.99.

hope this !

5x+40

5(x + 8)

7x - 49

7(x - 7)

18x + 9

9(2x + 1)

15x - 10

5(3x - 2)

step-by-step explanation:

for number one all you have to do is factor 5 out of 5x + 40

for number 2 factor 7 out of 7x - 49

for number three factor 9 out of 18x + 9

for number four factor 5 out of 15x - 10