What is the cost of six filters if eight filters cost $39.92?

To find the cost of six filters, we need to find the cost of one filter and multiply that by 6.

So the problem gives us the cost of eight filters! So we can arrange this as a fraction like this:    39.92 / 8
(The cost is ALWAYS the numerator) 

So now if we punch that into our calculator we get 4.99 or 4.99/1

That is the cost of one filter!

So now to find the cost of six filters, we multiply 4.99 by 6.

And we get... 29.94

So the cost of six filters is $29.94