15 parts per million of 3 harmful pollutants.the first amount was double the second. the 3 pollutant was 75% of the second.

Question

how many parts per million of each pollunant were found  could you provide steps?

Answer 1

The first amount = 2x

The second amount = x

The third pollutant = 0.75x

 

2x + x + 0.75x = 15/1,000,000

 

3x + 0.75x = 15/1,000,000 (combine like terms)

3.75x = 15/1,000,000 (combine like terms)

x = (15/1,000,000) divided by 3.75 (divide each side by 3.75)

x = (15/3.75)/1,000,000 (divide numerator by 3.75, as we use 1,000,000 as a standard measure)

x = 4 parts per million (divide)

 

The first pollutant = 2x = 2(4) = 8 parts per million (substitute & multiply)
The second pollutant = x = 4 parts per million (substitute)
The third pollutant = 0.75x = 0.75(4) = 3 parts per million (substitute & multiply)

 

Check your answer: 8+4+3=15