Answer:
I think x = 1 and y = 1/2. For the second: x = -1 4/13 or -1.307692, y = 4 1/4 or 4.25
Step-by-step explanation:
Answer:
7.8
Step-by-step explanation:
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<em><u>Answer:</u></em>
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<em><u>13 and 5</u></em>
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<em><u>Step-by-step explanation:</u></em>
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<em><u>x+y=18</u></em>
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<em><u>x-y=8</u></em>
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<em><u>_____</u></em>
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<em><u>2x=26</u></em>
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<em><u>x=13</u></em>
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<em><u>So the first number must be 13</u></em>
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<em><u>13+y=18</u></em>
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<em><u>y=5</u></em>
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<u><em>And the second number must be 5</em></u>
Answer:
- <u>120 pens and 200 pencils.</u>
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Explanation:
You can set a system of two equations.
<u>1. Variables</u>
<u />
- x: number of pens
- y: number of pencils
<u>2. Cost</u>
- <em>each pen costs</em> $1, then x pens costs: x
- <em>each pencil costs</em> $0.5, then y pencil costs: 0.5y
- Then, the total cost is: x + 0.5y
- The cost of the whole purchase was $ 220, then the first equation is:
x + 0.5y = 220 ↔ equation (1)
<u>3. </u><em><u>There were 80 more pencils than pens</u></em>
Then:
pencils = 80 + pens
↓ ↓
y = 80 + x ↔ equation (2)
<u>4. Solve the system</u>
i) Substitute the equation (2) into the equation (1):
ii) Solve
iii) Substitute x = 120 into the equation (2)
Solution: 120 pens and 200 pencils ← answer
<span>Since there are 5280 feet per mile:
22 miles/hr * 5280 feet/mile
= 116160 feet per hour
</span>
