A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • one year ago

The fifth term of an arithmetic progression is 28 and the tenth term is 58. Find the first term and the common difference. Please help! I tried 58=28+4d but that didn't work.

  • This Question is Closed
  1. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Do you have options?

  2. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I am sorry I don't really know what you mean?

  3. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Sorry! I meant, is it multiple choice?

  4. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Oh! No it isn't. But I do have the answers: d=6 first term=4

  5. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I just don't know how they got there. I have been taught some equations to work out the sum of a arithmetic series, to find the number of terms and so on but I don't know how to apply them here.

  6. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    So one thing to note (if you don't know this) with arithmetic patterns, it works in the way that they always add the same thing to get to each number.

  7. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Yes

  8. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    1. 4 2. ? 3. ? 4. ? 5. 28 What number can you continue to add 3 times and get to 28 from four? (I know the answer, but I want you to understand it :) )

  9. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Well, I understand the concept but actually I am not sure how to figure it out except for trail and error, is that how you are meant to figure it out?

  10. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    If I subtract four from 28 then divide the answer by four I get 6. But I don't know if that is just chance

  11. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Well, because these are such small numbers, yes. Trial and error would be the best. And yep! 6 is correct! And if you're worried it's just a coincidence, then you can do it all the way up through 58 and it will work! See: 4, 10, 16, 22, 28, 34, 40, 46, 52, 58. Tada! :D

  12. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Yay! Ok so I do I know without having the first number, and is there an equation for it?

  13. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Well the equation would be x + 6. And, without the first number, you could have just done it from 28 to 58: 28, 34, 40, 46, 52, 58. 6 Would still be the only number that would work. :)

  14. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Ok, how would I find the first term now? Would I use a + (k-1)d and rearrange to find a = (k-1)d ?

  15. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    I honestly don't know how I would make an equation to show it, but you can simply subtract 6 from 28 repeatedly until you get to what would be the first term. 4th: 22 3rd: 16 2nd: 10 1st: 4 I'm sorry I don't know the actual equations though! :(

  16. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    No thats ok, that makes sense and it works so no problem. How practical would that be for larger numbers though?

  17. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Well, if you have a calculator, it would be just as simple. And I would still use it, as long as they didn't go up into the millions. Is this a homework assignment? Or do you do online school?

  18. anonymous
    • one year ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Ok, just making sure! No, I am home-schooled. I find this site super helpful as often I find myself stuck on really little things which I have looked at for so long that I can't see my mistake anymore! Or just to easily find an equation I have missed or something. Thank you very much for your help, much appreciated.

  19. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.