Bodhi has a collection of 175 dimes and nickels. The collection is worth $13.30. Which equation can be used to find n, the number of nickels in the collection?

0.1n + 0.05(n – 175) = 13.30
0.1n + 0.05(175 – n) = 13.30
0.1(n – 175) + 0.05 = 13.30
0.1(175 – n) + 0.05n = 13.30

Question

Bodhi has a collection of 175 dimes and nickels. The collection is worth $13.30. Which equation can be used to find n, the number of nickels in the collection?

0.1n + 0.05(n – 175) = 13.30
0.1n + 0.05(175 – n) = 13.30
0.1(n – 175) + 0.05 = 13.30
0.1(175 – n) + 0.05n = 13.30

izze2004 · Answer

i really need help and fast

justjm · Answer

denote d=dimes and n=nickels. Make a system of equations.

We can say that 
$n+d=175$

Recall that n=$0.05 and d=$0.1
We can then say that
$0.05n+0.1d=13.30$

Now you have two systems. It seems like your options have decided to continue using substitution. 
$(1)...n+d=175$
$(2)...0.05n+0.1d=13.30$
Rearranging equation 1 is much easier than 2, so that's how we can continue.
$d=175-n$
Substitute the expression for d into $0.05n+0.1d=13.30$ and that should arrive you to your answer.