How much lead concentration was determined on a window sill that measured 2"x20" and yielded 60 ug?

How much lead concentration was determined on a window sill that measured 2"x20" and yielded 60 ug?

• A. 150 ug/ft²
• B. 180 ug/ft²
• C. 216 ug/ft²
• D. 240 ug/ft²

Answer: (C)

To determine the lead concentration per square foot on the window sill, it's essential to calculate the area of the window sill first. The dimensions given are 2 inches by 20 inches. 1. **Convert the dimensions from inches to feet:** - The width of the window sill: 2 inches = 2/12 feet = 1/6 feet. - The length of the window sill: 20 inches = 20/12 feet = 5/3 feet. 2. **Calculate the area of the window sill in square feet:** Area = Width × Length Area = (1/6) feet × (5/3) feet = 5/18 square feet. 3. **Now, to find the lead concentration in micrograms per square foot (ug/ft²):** The total lead measured is 60 micrograms. To find the concentration, you divide the total lead by the area in square feet: Lead concentration = Total lead / Area = 60 ug / (5/18) ft². 4. **Calculating the division:** - Dividing by a fraction is the same as multiplying by its reciprocal, so:

To determine the lead concentration per square foot on the window sill, it's essential to calculate the area of the window sill first. The dimensions given are 2 inches by 20 inches.

1. Convert the dimensions from inches to feet:

• The width of the window sill: 2 inches = 2/12 feet = 1/6 feet.

• The length of the window sill: 20 inches = 20/12 feet = 5/3 feet.

2. Calculate the area of the window sill in square feet:

Area = Width × Length

Area = (1/6) feet × (5/3) feet = 5/18 square feet.

3. Now, to find the lead concentration in micrograms per square foot (ug/ft²):

The total lead measured is 60 micrograms.

To find the concentration, you divide the total lead by the area in square feet:

Lead concentration = Total lead / Area = 60 ug / (5/18) ft².

4. Calculating the division:

• Dividing by a fraction is the same as multiplying by its reciprocal, so: