Answer:

Step-by-step explanation:
From the question we are told that:
Cost Price 
Sale Price 
Generally the equation for Profit P is mathematically given by



Therefore as a percentage
Percentage Profit X is given as


X=5, should be right correct me if i’m wrong.
Answer:
-2x² - 8x + 15 = 0
Step-by-step explanation:
Given the following algebraic expression;
x² – 7x + 5
-3x² - x + 10
To add the equation together;
x² – 7x + 5 + (-3x² - x + 10) = 0
x² – 7x + 5 - 3x² - x + 10 = 0
Collecting like terms, we have;
(x² - 3x²) - (7x + x) + (5 + 10) = 0
-2x² - 8x + 15 = 0
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Define x :
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Let Cheryl be x years old.
Cheryl = x
Lisa = x + 6
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In two years time:
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Cheryl = x + 2
Lisa = x + 8
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Lisa will be twice as old as Cheryl :
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x + 8 = 2(x + 2)
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Solve x :
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x + 8 = 2(x + 2)
x + 8 = 2x + 4
x = 4
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Find their age :
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Cheryl = x = 4
Lisa = x + 6 = 4 + 6 = 10
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Answer: Lisa is 10 years old now.
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