Results 1 to 3 of 3

Math Help - Setting up and solving equations to finding the number of stamps

  1. #1
    Junior Member
    Joined
    Feb 2009
    Posts
    63

    Exclamation Setting up and solving equations to finding the number of stamps

    Peter has 35 stamps. Some are valued at 2 cents, others at 5-cents, and the remainder at 10 cents. he has three times as many 5-cent stamps as he has 2-cent stamps and the total value of all stamps is $1.89. How many of each stamp does he have?
    Last edited by mr fantastic; October 17th 2009 at 09:45 PM. Reason: Changed post title
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Like a stone-audioslave ADARSH's Avatar
    Joined
    Aug 2008
    From
    India
    Posts
    726
    Thanks
    2
    Quote Originally Posted by Tessarina View Post
    Peter has 35 stamps. Some are valued at 2 cents, others at 5-cents, and the remainder at 10 cents. he has three times as many 5-cent stamps as he has 2-cent stamps and the total value of all stamps is $1.89. How many of each stamp does he have?
    Let he has x stamps of 10 cent
    y of 2cent and z of 5 cent
    so equations will be

    10x+2y+5z=189

    3y=z

    x+y+z=35

    Go ahead and try to show some steps next time, it will solve the problem permanently
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Grandad's Avatar
    Joined
    Dec 2008
    From
    South Coast of England
    Posts
    2,570

    Word problem

    Hello Tessarina
    Quote Originally Posted by Tessarina View Post
    Peter has 35 stamps. Some are valued at 2 cents, others at 5-cents, and the remainder at 10 cents. he has three times as many 5-cent stamps as he has 2-cent stamps and the total value of all stamps is $1.89. How many of each stamp does he have?
    Let's suppose he has x 2-cent stamps. They are (obviously) worth 2 cents each. So altogether they are worth 2x cents.

    He has three times as many 5-cent and 2-cent stamps. If he has x 2-cent stamps, how many 5-cent stamps is that? (You need to multiply.) So how much will they be worth altogether? (You need to multiply again.)

    Now he has 35 stamps altogether. To find out how many 10-cent stamps, add together the number (not their value) of 2-cent and 5-cent stamps (that's x plus whatever number of 5-cent stamps he has), and take the total away from 35. This will give you something like 35 - (something) x. Now multiply this number by 10 to find out how much they are worth.

    Then: add together the value of all the stamps, and put the total equal to 189. So you'll get an equation like:

    2x + (something) x + (something-else) = 189.

    Then solve this equation for x's, and you're there.

    Can you do that?

    Grandad
    Last edited by Grandad; February 12th 2009 at 02:36 AM. Reason: Re-phrased last method
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 5
    Last Post: August 4th 2011, 02:36 PM
  2. Replies: 1
    Last Post: March 3rd 2011, 07:42 PM
  3. Replies: 3
    Last Post: February 10th 2010, 08:01 PM
  4. Setting up a system of equations! + Matrix solving
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: October 21st 2009, 07:31 PM
  5. Replies: 22
    Last Post: July 2nd 2009, 10:13 PM

Search Tags


/mathhelpforum @mathhelpforum