Adam has $2.15 in nickels, dimes and quarters in his pocket. If the number of dimes is 4 less than the number of nickels, and 5 more than the number of quarters, then how many of each type of coin does he have?

Respuesta :

Answer: nickels = 12, dimes = 8, quarters = 3

Step-by-step explanation:

First, set up the equations for each coin:

[tex]\begin {array}{c|c|c|l}\underline{\quad Type\quad }&\underline{Value}&\underline{Quantity}&\underline{\qquad \qquad \qquad Equation\qquad }\\ Nickel& \$0.05&4+d&0.05(4+d) = 0.20 + 0.05d\\Dime& \$0.10&d&\qquad 0.10(d)=0.10d\\Quarter& \$0.25&d-5&0.25(d-5)=0.25d-1.25\\\end{array}[/tex]

Next, the sum of the coins is $2.15 so substitute and solve for the variable:

   Nickels         +   Dimes  +     Quarters     =   Sum

0.20 + 0.05d  +    0.10d   +   0.25d - 1.25   =  2.15

           0.40d - 1.05 = 2.15

           0.40d           = 3.20

                  d            = 8

Lastly, plug the d-value into the quantity equation for the nickels and quarters to find their quantity.

nickels: 4 + d   = 4 + (8)   = 12

quarters: d - 5   = (8) - 5   = 3

The number of coins of nickels are [tex]\boxed{12}[/tex], the number of coins of dimes are [tex]\boxed{8}[/tex] and the number of coins of quarters are [tex]\boxed{3}.[/tex]

Further explanation:

Given:

Adam has [tex]\$ 2.15[/tex] in nickels, dimes and quarters.

If the number of dimes is 4 less than the number of nickels, and 5 more than the number of quarters.

Explanation:

Consider the number of coins of nickels as [tex]x[/tex].

Consider the number of coins of dimes as [tex]y[/tex].

Consider the number of coins of quarters as [tex]z[/tex].

The value of nickel in dollar is [tex]\$ 0.05.[/tex]

The value of dime in dollar is [tex]\$ 0.10.[/tex]

The value of quarter in dollar is [tex]\$ 0.25.[/tex]

If the number of dimes is 4 less than the number of nickels

[tex]x = \left( {4 + y} \right)[/tex]

If the number of dimes5 more than the number of quarters

[tex]z = y - 5[/tex]

Adam has [tex]\$ 2.15[/tex] in nickels, dimes and quarters.

[tex]\begin{aligned}0.05x + 0.10y + 0.25z &= 2.15\\0.05\left( {4 + y} \right) + 0.10y + 0.25\left( {y - 5} \right) &= 2.15\\0.40y - 1.05&= 2.15\\0.40y &= 3.20\\y&= 8\\\end{aligned}[/tex]

Number of nickels are 12.

Number of quarters are 3.

The number of coins of nickels are [tex]\boxed{12}[/tex], the number of coins of dimes are [tex]\boxed{8}[/tex] and the number of coins of quarters are [tex]\boxed{3}.[/tex]

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Answer details:

Grade: High School

Subject: Mathematics

Chapter: Polynomial

Keywords: Adam, $2.15, nickels, dimes, quarters, pocket, number, less, less than, 5 more than, coin, number of quarters.

Q&A Education