Let the number of nickels be = x
Let the number of dimes be = d
Let the number of quarter be = n
Given is, she has twice as many dimes as quarters
d=2n or n = 0.5d
She has two less quarters than nickles.
n= x-2 or
x= n+2
Total values of coins is = $2.60
[tex]0.05x+0.10d+0.25n=2.60[/tex]
Now replace x with (n+2) and d with 2n
[tex]0.05(n+2)+0.10(2n)+0.25n=2.60[/tex]
[tex]0.05n+0.10+0.20n+0.25n=2.60[/tex]
[tex]0.50n+0.10=2.60[/tex]
[tex]0.50n=2.50[/tex]
[tex]n=5[/tex]
Now x=n+2 ; x=5+2 = 7
d=2n ; d=2(5) = 10
Hence, Elina has 7 nickels, 10 dimes and 5 quarters.