Answer:
84 ounces of pure gold
Step-by-step explanation:
Jess has 60 ounces of an alloy that is 40% gold. How many ounces of pure gold must be added to this alloy to create a new alloy that is 75% gold?
Pure gold = 100% gold
Let the number of ounces of pure gold = x
Hence, we have the equation
40% × 60 ounces + 100%× x ounces = 75%(60 + x)ounces
= 0.4 × 60 + 1x = 0.75(60 + x)
= 24 + x = 45 + 0.75x
Collect like terms
x - 0.75x = 45 - 24
0.25x = 21
x = 21/0.25
x = 84 ounces
Therefore, we need 84 ounces of pure gold
<span>The correct answer is: Option (C) $1393.21
Explanation:
At the beginning of the Second year, the total balance would be:
$1200 + ($1200 * 7.75 / 100) = $1293
At the beginning of the Third year, the total balance would be:
$1293 + ($1293 * 7.75 / 100) = $1393.21 (Option C)</span>
7 is incorrect. The answer should be -4. Here's how I'd derive it:
With 
, we should expect 
. If 
, then
Also,
so we should expect 
and
You seem to be taking
but this is not an identity.
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8 is incorrect. Just a silly mistake, you swapped the order of the terms in the numerator. It should be
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9. Use the identity from (7). 
lies in the second quadrant, so
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12.
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13.
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14.
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15.
3/4 X 7/1=5 1/4 Then, 5 1/4+5 1/4=10 1/2. Answer 10 1/2
