Let x represent the number of liters of 50% acid Theresa puts into the mix. The the number of liters of 30% acid will be (420-x). The total amount of acid in the final solution will be ...
0.50x + 0.30(420-x) = 0.45(420)
0.20x + 126 = 189 . . . . . . . . . . . . . . . simplify
0.20x = 63 . . . . . . . . . . . . . . . . . . . . . subtract 126
x = 63/0.20 = 315 . . . . . . . . . . . . . . . liters of 50% solution
(420-x) = 420-315 = 105 . . . . . . . . . liters of 30% solution
Theresa should mix ...
105 liters of 30% solution
315 liters of 50% solution
20 percent of 40 is 8. As a fraction that would be 8/1.
Hope this helps
<em>Answer:</em>
<em>There would be 173,535 lionfish after 6 years.</em>
<em>Step-by-step explanation:</em>
<em>Since lionfish are considered an invasive species, with an annual growth rate of 67%, ya scientist estimates there are 8,000 lionfish in a certain bay after the first year, A) to write the explicit equation for f (n) that represents the number of lionfish in the bay after n years; B) determine how many lionfish will be in the bay after 6 years; and C) if scientists remove 1,200 fish per year from the bay after the first year, determine what is the recursive equation for f (n); the following calculations must be performed:</em>
<em></em>
<em>A)</em>
<em>8000 x 1.67 ^ n = f </em>
<em>B)</em>
<em>8000 x 1.67 ^ 6 = X</em>
<em>8000 x 21.691961596369 = X</em>
<em>173,535.692770952 = X </em>
<em>C)</em>
<em>(8000 - 1200 x 1 ^ n) x 1.67 ^ n = f</em>
<em>Therefore, there would be 173,535 lionfish after 6 years.</em>
Answer:
$13,671
Step-by-step explanation:
Each stamp cost $1,953, and the collector bought 7 of them.
1953 * 7 = 13671
The collector spent $13,671 on the stamps.