To find the total of the measurements 28 L, 42 L, 6 L, and 931 L, we first add them together:
\[ 28 , \text{L} + 42 , \text{L} + 6 , \text{L} + 931 , \text{L} = 1,007 , \text{L} \]
Next, we must determine the correct number of significant figures in the total.
- The number 28 L has 2 significant figures.
- The number 42 L has 2 significant figures.
- The number 6 L has 1 significant figure.
- The number 931 L has 3 significant figures.
The result should be rounded to the least number of decimal places present in the measurements being added, which in this case is 0 decimal places (the measurement with the lowest number of significant figures is 6 L, which has 1 significant figure).
Since our total is 1,007 L, it has 4 significant figures. However, rounding it to the appropriate number of significant figures, we express it as:
\[ 1,000 , \text{L} \]
Thus, the correct total rounded to the appropriate significant figures is 1,000 L.