Answer:
The weight of the mystery substance added by Tim is 4.07 ounces. Hence option A is correct.
Solution:
Given, Tim is measuring the weight (in ounces) of a substance for a science experiment.
Tim added a mystery substance (m) to his experiment.
Tim used the equation 12.93 + m = 17.0 to find out how much he added.
We have to find how much of the mystery substance (m) did Tim add to his experiment?
Now, from the given equation, 12.93 + m = 17.0 → m = 17.0 – 12.93 → m = 4.07
Hence, the weight of the mystery substance is 4.07 ounces, i.e. option A is correct.