Question

Every year, approximately 25,000,000 kg of hair is cut in the U.S. Each kg of hair contains about 0.0002 kg of zinc, and each kg of zinc is worth about 4 dollars. How many dollars worth of zinc is contained in the hair cut in the U.S. annually?

Answer 1

20,000 u$S

Explanation:

First of all let's calculate how many kg of Zinc we obtain of hear cuts in an year:

• 25,000,000 Kg of hair.
• For each kg of hair we obtain 0.0002 kg of zinc

So, if we multiply, we can obtain the quantity of zinc:

25,000,000 kg of hair * 0.0002 kg of zinc/kg of hair = 5,000 kg of zinc

Now, if every kilo of zinc worth 4 dollars:

• 5000 kg of zinc *4 U$S/Kg of zinc = 20,000 U$S

Answer 2

The annual haircut in the United States contains $ 20,000 from zinc

Explanation:

1 kg of hair contains ___________________ 0.0002 kg of zinc

25,000,000 kg of hair _________________ X

`X=(25,000,000 kg of hair X 0.0002 kg of zinc)/(1 kg of hair)= 5,000 kg of zinc`

It means that 25,000,000 kg of hair contains 5000 kg of zinc.

Otherwise,

If 1 kg of zinc _____________ worths $4

5,000 kg of zinc___________ X

`X=(5000 kg of zinc x 4$)/(1kg of zinc)`

X= $20,000