Results 1 to 4 of 4

Thread: Original Principle, different rates/investment

  1. #1

    Original Principle, different rates/investment

    Linus and Macy put the same amount of money into different investments for one year. Linus' investments increased by 8%. Macy's investments decreased by 7%. The difference in the value of their investments was $750 after the one year. What was the original amount of money that each invested?
    How do I start to solve this?
    Do I just substitute the known values into I=PRT and solve for P, or is there a different equation that is meant to be used.

  2. #2
    Elite Member
    Join Date
    Feb 2004
    Location
    Ottawa, Ontario
    Posts
    16,652
    Hint:
    a = amount invested
    a@8% - a@-7% = 750
    a(1 + .08) - a(1 - .07) = 750
    Solve for a
    I'm just an imagination of your figment !

  3. #3
    Quote Originally Posted by Denis View Post
    Hint:
    a = amount invested
    a@8% - a@-7% = 750
    a(1 + .08) - a(1 - .07) = 750
    Solve for a
    a(1 + 0.08) - a(1 -0.07) = 750
    a(1.08) - a(0.93) = 750
    1.08 - 0.93 = 0.15
    0.15 * a = 0.15a
    750/0.15 = a
    a = 5000
    This is correct right?

  4. #4
    Elite Member
    Join Date
    Feb 2004
    Location
    Ottawa, Ontario
    Posts
    16,652
    Quote Originally Posted by SaltyPoro View Post
    a(1 + 0.08) - a(1 -0.07) = 750
    a(1.08) - a(0.93) = 750
    1.08 - 0.93 = 0.15
    0.15 * a = 0.15a
    750/0.15 = a
    a = 5000
    This is correct right?
    YESSSSSSSSS!
    You get a stick-on pink star for your forehead
    You can check if correct:
    5000 * .08 = 400
    5000 * -.07 = -350
    400 - (-350) = 750 ; OK?
    I'm just an imagination of your figment !

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •