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JazzySarah4 Group Title

Many highways have signs along the side of the road that list your mileage from some place behind you. You are driving down a highway and notice a milepost showing distance that is a two-digit number. Exactly one hour later, you notice a milepost that shoes the same two digits as the first, in opposite order. Then, exactly one hour after seeing the second milepost, you notice a third one that shows a three-digit number. The middle digit on this sign is 0. The other two digits are the same as those on the first post and are in the same order as on the first milepost. How fast did you trave

  • 2 years ago
  • 2 years ago

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  1. Mr.Math Group Title
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    You're saying I'm driving away from the place the milepost indicates?

    • 2 years ago
  2. JazzySarah4 Group Title
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    Yes. So you are driving and the posts tell you mileage from a place behind you

    • 2 years ago
  3. Mr.Math Group Title
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    Okay, this is a nice one. Let's say the distance at time \(t_0=0\) hours was \(a_0a_1=10a_0+a_1\), then one hour later, it became \(a_1a_0=10a_1+a_0\). One hour after than, the distance became \(a_00a_1=100a_0+a_1.\) Assuming I was driving at speed \(x\) speed unit, then we can write the following system: \[10a_0+a_1+1\cdot x=10a_1+a_0\] \[10a_1+a_0+1\cdot x=100a_0+a_1\] \[10a_0+a_1+2\cdot x=100a_0+a_1\] Note: \(1\cdot x=x\). I wrote it this way to emphasis the units.

    • 2 years ago
  4. Mr.Math Group Title
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    Your job now, as you probably know, is to solve the above system for the variable \(x\).

    • 2 years ago
  5. JazzySarah4 Group Title
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    Sorry but the numbers are confusing me. Is there a way to write them more clearly? If I solve the system, I will get three variables. What do the variables represent? Because I am going to need a speed as my answer, right?

    • 2 years ago
  6. Mr.Math Group Title
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    Well, \(a_0\) represents the 10 place in the first milepost and \(a_1\) represents the 1 place in the first milepost. \(x\) is the speed of the car in \(\text{mph}\), assuming the given distances are in miles.

    • 2 years ago
  7. Mr.Math Group Title
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    Key note: Keep in mind that \(a_0\) and \(a_1\) are integers!

    • 2 years ago
  8. JazzySarah4 Group Title
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    Ah! Let me try something soon and then get back you !

    • 2 years ago
  9. Mr.Math Group Title
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    Good luck!

    • 2 years ago
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