Question

Each year, the Department of Water Works measures the chloride concentration level in the water. The first year, they found the chloride concentration changed by −1 3/5 mg/L . It is estimated that the chloride concentration will change −2 1/15 mg/L the next year.
What is the total change that will likely occur in 2 years?

Answer 1

-3 2/3 total change occurrence.

Answer 2

Answer:

$-2\frac{241}{360} mg /L$

Step-by-step explanation:

Givens

• The first year, the concentration is $-1 \frac{3}{5} mg/L$.
• The second year, the concentration is $-2\frac{1}{15} mg/L$.

To find the ratio of change, we just have to divide the second concentration with the first one

$-2\frac{1}{15} \div -1\frac{3}{5}=\frac{31}{15} \div \frac{8}{5}=\frac{31}{15} \times \frac{5}{8}=\frac{155}{120}= \frac{31}{24}$

So, we need to apply this ratio of change to find the concentration for the third year, because the question is asking for the concentration in 2 years

$-2\frac{1}{15} mg/L \times \frac{31}{24} =-\frac{31}{15} mg/L \times \frac{31}{24} =-\frac{961}{360} =-2\frac{241}{360} mg /L$

Therefore, the concentration is

$-2\frac{241}{360} mg /L$