Question

a chemical engineer must report the average volume of a certain pollutant produced by the plants under her supervision. here are the data she has been given by each plant:

plant	volume of pollutant
pinecrest	0.87 l
lincoln	20.2 l

what average volume should the chemical engineer report? be sure your answer has the correct number of significant digits.

Explanation:

Step1: Recall average formula

The formula for the average (arithmetic - mean) of a set of numbers $x_1,x_2,\cdots,x_n$ is $\bar{x}=\frac{x_1 + x_2+\cdots+x_n}{n}$. Here, $x_1 = 0.21$, $x_2=0.87$, $x_3 = 20.2$, and $n = 3$.

Step2: Calculate the sum

$S=0.21+0.87 + 20.2=21.28$.

Step3: Calculate the average

$\bar{x}=\frac{21.28}{3}\approx7.0933\cdots$.

Step4: Determine significant digits

The least number of significant digits among the original data values is 2 (in 0.21 and 0.87). So, we round the average to 2 significant digits. Rounding 7.0933 to 2 significant digits gives 7.1.

Answer:

7.1 L