When the use of significant figures and rounding up is applied correctly the mass of the mixture will be 80.5 g.
In cases of addition or subtraction, only the last significant figure of every number is taken into account.
In 30.05, this is 5, in the hundredths. When we look at 50.0, the last significant figure is 0, and it is in the tenths. And in 0.4006, the last significant figure is 6, in the ten thousandths. Of these three, the 0 from 50.0 is in the leftmost position, which means that the last significant figure of the result needs to be in the same position (in the tenths).
Moving onto the actual algebraic operation:
30.05 g + 50.0 g + 0.4006 = 80.4506 g
As we established, the last significant figure should be in the tenths, and we will have to round up 4 to 5 (trailing numbers are greater than 0), which means that the resulting mass will be 80.5 g.
You can learn more about significant figures here:
brainly.com/question/14804345
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