math

Sam has 18 coins in his pocket that are either quarters or nickels. The total value of these coins is $3.90.

Let q represent the number of quarters and n represent the number of nickels. The following system of equations represents this situation:

q+n=18

0.25q+0.05n=3.90

How many quarters and nickels does Sam have?

  1. 0
  2. 5
asked by j
  1. Substitute 18-q for n in the second equation and solve for q. Insert that value into the first equation to solve for n. Check by putting both values into the second equation.

    1. 0
    posted by PsyDAG
  2. idk fam

    1. 0
    posted by Anonymous
  3. 9
    i
    9
    o0
    0
    0

    1. 0
    posted by Anonymous
  4. what is ittttt I have to do my tenmarksssss

    1. 0
    posted by Anonymous
  5. I too have to do my tenmarks

    1. 0
    posted by Anonymous
  6. Lets first start with what is stated above~

    What we know:
    Q= Quarters
    N= Nickels
    Total amount= $3.90
    Total coins=18

    Q + N= Total coins (18)
    0.25Q(Quarter amount) + 0.05N (Nickel amount)= $3.90 (Total amount)

    Whenever you do problems like this in a systems of equations unit you MUST ALWAYS isolate only 1 letter, leaving only 1 OTHER letter behind as your new equation
    Q + N = 18
    -Q -Q
    New Equation-
    N= 18 - Q

    Your next step is simple, plug and chug (don't discriminate, my teacher taught it to me that way, I remember it better in the weirdest way, as you can see)
    0.25Q + 0.05(insert the N=18 - Q Equation here)= 3.90
    Then simply solve for the equation.

    0.25Q + 0.05(18 - Q)=3.90
    0.9 - 0.05Q=3.90
    Combine like terms
    0.25 + 0.9 - 0.05Q=3.90
    0.2Q + 0.9= 3.90
    -0.9 -0.9

    0.2Q/0.2 = 3/0.2
    Q = 15
    Now for the final step, go back to your N= 18 - Q Equation, and this time, insert your new Q

    N= 18 - Q
    N= 18 - (15)
    N= 3
    Your final results
    Nickels~3
    Quarters~15




    This section is for the people who need this equation for homework or for another reason.


    18 coins
    $3.90
    Q= Quarter (0.25)
    N= Nickel (0.05)

    Q + N = 18
    -Q -Q

    0.25Q + + 0.05 N =3.90

    N= 18 - Q

    0.25Q + 0.05(18 - Q)= 3.90

    0.25Q + 0.9 - 0.05Q= 3.90
    0.2Q + 0.9 = 3.90
    -0.9 -0.9

    0.2Q = 3
    _____ _____
    0.2 0.2

    Q = 15




    N= 18 - Q
    N= 18 - (15)
    N= 3

    1. 0
    posted by Ziyada

Respond to this Question

First Name

Your Response

Similar Questions

  1. math

    Grandpa has twenty - four coins in his pocket . grandpa gives Sam some clues the total value of the coins in his pocket one - sixth of coins are quarters , one - half of coins in dimes . what is the total value of the coins in
  2. Word problem

    What about this one guys, I tried setting it up like i was shown on the one similar but i keep getting a negative number. Kelsey has 32 coins in her pocket, all which are nickels and quarters, If the total value of her change is
  3. Algebra

    Kyle has 13 coins in his pocket that are either quarters or nickels. He has $2.05 in his pocket in coins. Let q represent the number of quarters and n represent the number of nickels. The following system of equations represents
  4. Algebra

    Solve the problem using matrices. John has a jarful of quarters and nickels. There are 84 coins in the jar. The value of the coins is $13.00. How many of each type of coin are there? A) 49 quarters ; 35 nickels B) 44 quarters; 40
  5. math

    Andrew has $2.75 in nickels and quarters in his coat pocket. If he has a total of 15 coins, which system of equations could you use to find the number of quarters in Andrews coat pocket? 1)x+y=15 0.5x+0.25y=2.75 2)x+y=2.75 x+y=15
  6. algebra

    How many coins When i dumped the change out of my pocket, I noticed that i could pay the exact price for any item from one cent up to and through one dollar without receiving any change. What is the fewest number of coins I could
  7. Mah

    Adam has 4 dimes, 4 quarters and 4 nickels in his pocket. He pulls out 2 coins making sure to put the first one back in his pocket before picking the second. What are the odds that he pulls out 2 nickels? A. 1/3 B. 1/9 C. 1/16 D.
  8. Math

    You have some quarters and some nickels in your pocket in total you have 7 coins and together they are worth 95 cents how many nickels and how many are quarters? I know the equations will have something to do with the 7 couns and
  9. Math

    jason has $1.56 in change in his pocket . if there is a total of 19 coins, how many quarters, dimes,nickels, and pennies does he have.
  10. math

    in his left pocket ralph has 4 quarters and 5 nickels. in his right pocket he has 3 quarters 2 nickels and 1 penny. if he wants to select a quarter at random, which pocket should he choose?

More Similar Questions