The amount of gold jewelry and other products is measured

in karats (K), where 24K represents pure gold. The mark 14K
on a chain indicates that the ratio between the mass of the
gold in the chain and the mass of the chain is . If a gold
ring is marked 18K and it weighs 0.4 oz, what is the value of
the gold in the ring if pure gold is valued at $300 per oz?

18K gold is 18/24 = 75% gold, by mass.

A 0.4 oz 18K ring therefore contains 0.3 oz of gold.

Multiply 0.3 oz by $300/oz for the gold value in the ring. The other 0.1 oz is probably copper of negligible value.

That is a rather outdated question. Gold is worth $1100/oz these days.

To solve this problem, we need to determine the mass of the gold in the ring and then calculate its value based on the given price per ounce.

First, let's determine the mass of the gold in the ring.

The mark "18K" indicates that the ratio between the mass of the gold in the ring and the total mass of the ring is 18:24 or 18/24.

Since the ring weighs 0.4 oz, we can use this information to calculate the mass of the gold in the ring:

Mass of gold in ring = (18/24) * 0.4 oz

Next, let's calculate the value of the gold in the ring based on the given price per ounce.

The pure gold is valued at $300 per ounce. So, the value of the gold in the ring can be calculated as:

Value of gold in ring = (mass of gold in ring) * (price per ounce)

Now, let's substitute the values into the equation:

Value of gold in ring = ((18/24) * 0.4 oz) * ($300/oz)

Simplifying the equation:

Value of gold in ring = 0.6 * $300

Finally, let's calculate the value:

Value of gold in ring = $180

So, the value of the gold in the ring is $180.