Answer:
the correct answer is 1/5
Step-by-step explanation:
Given:
The given equation is
To find:
All the real solutions.
Solution:
We have,
It can be written as
Using zero product property, we get
and 
and 
and 
We know that is an imaginary number because there is a negative sign under the square root.
Therefore, is the only real solution of the given equation.
Set of equations that can be used to calculate rate for each plumber:
2A+8B+8C = 1,400 --- (1)
4A+7B+10C = 1,660 --- (2)
3A+9B+9C = 1,660 --- (3)
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2*(1) - (2)
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4A+16B+16C = 2,800
4A+7B+10C = 1,660 -
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9B+6C = 1,140 --- (4)
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3(2) -4(3)
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12A+21B+30C = 4,980
12A+36B+36C = 6,600 -
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-15B-6C = -1,620 --- (5)
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(4) + (5)
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9B+6C = 1140
-15B-6C = -1620 +
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-6B = -480 => 6B = 480 => B = 480/6 = 80
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Using (4), 9(80)+6C = 1140
720+6C = 1140 => 6C = 1140-720 = 420 => C = 420/6 = 70
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Using (1), 2A+8(80)+8(70) = 1400
2A+640+560 =1400 => 2A = 1400-640-560 = 200 => A = 200/2 = 100
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The rates are:
A = $100
B = $80
C = $70
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On Thursday, number of calls: A = 4 hrs, B = 6 hrs, C = 3 hrs
Money earned = 4*100+6*80+3*70 = $1,090
There are 10 people and you want each of them to have 3 cupcakes. So multiply 10x3, which is 30. Then divide 30 by 8. You can't do that without a remainder though. So you round up to the nearest multiple of 8, which is 32. Then divide 32 by 8, which is 4. So tell dad to bake 4 batches, and the rest is for your dessert tomorrow.
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hope it helps
