Question

one canned juice drink is 25% orange juice ; another is 10% orange juice. how many liters of each should be mixed towing order to get 15L that is 13% orange juice?

Answer 1

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Assumptions
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Let x be the amount of 25% orange juice
Let y be the amount of 10% orange juice

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There are 15 litres of 13% orange juice
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x + y = 15

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The 15 litres of juice is 13% orange juice
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0.25x + 0.1y = 15 x 0.13
0.25x + 0.1y = 1.95

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Rewrite the equations and solve for x and y
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x + y = 15 ----------------------- (Equation 1)
0.25x + 0.1y = 1.95 ----------- (Equation 2)

(Equation 1):
x + y = 15
x = 15 - y  ----------- (Substitute into Equation 2)

0.25 (15 - y) + 0.1y = 1.95
3.75 - 0.25y + 0.1y = 1.95
0.15y  = 1.8 
y = 18 ÷ 0.15
y = 12 ------------- (substitute into Equation 1)

x + y = 15
x + 12  = 15
x = 15 - 12
x = 3

x = 3 and y = 12

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Answer: 3 liters of 25% of orange juice with 12 liters of 10% orange juice
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