Neal B. answered • 10/01/15

Math & Physics with Neal (Masters Degree in Applied Physics)

Lily F.

10/01/15

Lily F.

asked • 10/01/15If I have 29 spiders AND flies, and there are a total of 192 legs between them, how many spiders are there? How many flies?

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Neal B. answered • 10/01/15

Math & Physics with Neal (Masters Degree in Applied Physics)

Use all the information given and use it to form two equations.

Think about how many legs a spider has and how many legs a fly has.

Lily F.

thank you so much Neal and Mark! I get it now!

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10/01/15

Mark M. answered • 10/01/15

Mathematics Teacher - NCLB Highly Qualified

s + f = 29

8s + 6f = 192

8s + 8f = 232

8s + 6f = 192

2f = 40

f = 20

You have twenty flies and nine spiders.

Neal B.

tutor

I thought these were the guidelines, "Answering questions in a way that leads a student to understand how to arrive at the answer is preferable to just providing the answer."

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10/01/15

Lily F.

I don't understand y you multiplied s+f by 8. Can you explain?

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10/01/15

Mark M.

tutor

The process is "solving systems by elimination." I selected 8 since I could subtract the bottom equation from the top equation and eliminate the "s."

I could have multiplied by 6 to eliminate the f. The results would be the same.

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10/01/15

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Lily F.

10/01/15