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3 years ago

A mixture of 30 pounds of candy sells for $1.10 a pound. The mixture consists of chocolates worth $1.50 a pound and chocolates w

orth 90¢ a pound. How many pounds of the $1.50 chocolate were used to make the mixture?
A)15
B)10
C)12

Mathematics

1 answer:

astra-53 [7]3 years ago

3 0

$x-chocolate\ worth\ 1,50\$ \ per\ pound\\
y-chocolate\ worth\ 0,9\$\ per\ pound\\
\\\\
 \left \{ {{x+y=30} \atop {30*1,10=x*1,50+y*0,9}} \right.\\\\ \left \{ {{x=30-y} \atop {33=1,5x+0,9y}} \right. \\\\ Using \ substitution\ method:\\\\33=1,5(30-y)+0,9y\\\\
33=45-1,5y+0,9y\\\\ -12=-0,6y\ |:-0,6\\\\
y=20\\
x=10$

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Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

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Solution to the problem

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And if we replace the values obtained we got this:

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________________________
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________________________
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