SOLUTION: The manager of a fish store has water that is 10% salt and the other water that is 25%. He needs to fill an aquarium with 10 gallons of water that is 20%. what is the answer?

Algebra ->  Coordinate Systems and Linear Equations  -> Linear Equations and Systems Word Problems -> SOLUTION: The manager of a fish store has water that is 10% salt and the other water that is 25%. He needs to fill an aquarium with 10 gallons of water that is 20%. what is the answer?      Log On


   



Question 1096495: The manager of a fish store has water that is 10% salt and the other water that is 25%. He needs to fill an aquarium with 10 gallons of water that is 20%. what is the answer?
Found 3 solutions by Alan3354, Fombitz, josmiceli:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
The manager of a fish store has water that is 10% salt and the other water that is 25%. He needs to fill an aquarium with 10 gallons of water that is 20%. what is the answer?
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Depends on the question.
Here's a similar problem.
Same problem, different numbers, actually.
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A scientist mixes water (containing no salt) with a solution that contains
40% salt. She wants to obtain 200 ounces of a mixture that is 5% salt. How many ounces of water and how many ounces of the 40% salt solution should she use
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W = Water
S = 40% salt (if available)
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W + S = 200
W*0 + S*40 = (W+S)*5
40S = 5W + 5S
5W = 35S
W = 200-S
5(200-S) = 35S
1000 - 5S = 35S
40S = 1000
S = 25

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let A be the amount of 10% water and B the amount of 25% water.
1.A%2BB=10
and
+10A%2B25B=20%28A%2BB%29+
10A%2B25B=20%2810%29
10A%2B25B=200
2.2A%2B5B=40
From 1,
2A%2B2B=20
2A=20-2B
Substituting into 2,
%2820-2B%29%2B5B=40
3B=20
Solve for B, then use either equation to solve for A.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +a+ = gallons of 10% salt water needed
Let +b+ = gallons of 25% salt water needed
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(1) +a+%2B+b+=+10+
(2) +%28+.1a+%2B+.25b+%29+%2F+10+=+.2+
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(2) +.1a+%2B+.25b+=+2+
(2) +10a+%2B+25b+=+200+
(2) +2a+%2B+5b+=+40+
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Multiply both sides of (1) by +2+
and subtract (1) from (2)
(2) +2a+%2B+5b+=+40+
(1) +-2a+-2b+=+-20+
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+3b+=+20+
+b+=+6.667+
and
(1) +a+%2B+6.667+=+10+
(1) +a+=+3.333+
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3.333 gallons of 10% salt water needed
6.667 gallons of 25% salt water needed
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check:
(2) +%28+.1a+%2B+.25b+%29+%2F+10+=+.2+
(2) +%28+.1%2A3.333+%2B+.25%2A6.667+%29+%2F+10+=+.2+
(2) +%28+.3333+%2B+1.6667+%29+%2F+10+=+.2+
(2) +2%2F10+=+.2+
(2) +.2+=+.2+
OK