Answer:
we have 5 nickels and 7 dimes
Step-by-step explanation:
We have a total of 12 coins; n nickels and d dimes. So, the nickels and dimes that I own are 12 altogether or:
[tex]n + d =12[/tex]
My second piece of information tells me that the value of my coins equals $0.95 We know that a nickel is worth $0.05 and a dime is worth $0.10:
[tex]0.05n + 0.10d = 0.95[/tex]
So our systems of equations are as follows:
[tex]\left \{ {{n + d =12} \atop {0.05n + 0.10d = 0.95}} \right.[/tex]
we solve for d and remplace in the second equation
[tex]d=12-n[/tex]
[tex]0.05n + 0.10(12-n) = 0.95[/tex]
isolate n an we get:
[tex]0.05n + (12*0.10)-0.10n = 0.95\\[/tex]
[tex]0.25=0.05n[/tex]
[tex]n=5\\[/tex]
and we replace n=5 in the first equation:
[tex] d =12-5=7[/tex]
we have 5 nickels and 7 dimes