Answer:
10 nickels and 10 quarters
Step-by-step explanation:
Given
Number of coins: 20
Vaiue of coins = $3.00
Required
Number of Nickels and Quarters;
Let N =Nickels and Q =Quarters
The total coins is represented as:
[tex]N + Q = 20[/tex]
1 nickel is equivalent to $0.05 and 1 quarter is equivalent to $0.25; So
[tex]0.05N + 0.25Q = 3[/tex]
Make N the subject of formula in the first equation
[tex]N = 20 - Q[/tex]
Substitute this in the second equation
[tex]0.05(20 - Q) + 0.25Q = 3[/tex]
[tex]1 - 0.05Q + 0.25Q = 3[/tex]
Collect like terms
[tex]-0.05Q + 0.25Q = 3 - 1[/tex]
[tex]0.2Q = 2[/tex]
Multiply both sides by 5
[tex]5 * 0.2Q = 2 * 5[/tex]
[tex]Q = 10[/tex]
Recall that N = 20 - Q
[tex]N = 20 - 10[/tex]
[tex]N = 10[/tex]