Question

The pollution count in a bay was 68.0 parts per million. This was an increase of 9.4% over the previous year. What, to the nearest tenth of a part per million, was the pollution count in the previous year?

Answer 1

To find the pollution count in the previous year, we can use the percentage increase and the given pollution count for the current year.

Let x be the pollution count in the previous year.

We know that the pollution count in the current year is 68.0 parts per million, and this is an increase of 9.4% over the previous year.

So, we can set up the equation:

x + 0.094x = 68.0

Solving for x:

1.094x = 68.0

x = 68.0 / 1.094

x ≈ 62.17

So, to the nearest tenth of a part per million, the pollution count in the previous year was approximately 62.2 parts per million.