Diamond and silver rings.

Question

$2$ diamond rings and $4$ silver rings cost $\$1440$. A diamond ring and a silver ring cost $\$660$. How much does a silver ring cost?

Answer 1

How much do two diamond rings and two silver rings costs?

Can you subtract that from the first equation, leaving only two silver rings?

Answer 2

Let the cost of a diamond ring be $x$ and the cost of a silver ring $y$.

Now

$2x+4y=1440$

$x+y=660$

Solve this system of equations for $y$.