Suppose that a series of measurements have shown that the mean mass of an object is 122.4g with
deviation of 1.3 g. how many significant figures are justified in the mean and how would you report the
most probable mass of the object? explain.

Explanation:

If the deviation is 1.3 g the true measurement will be within the interval 122.4g - 1.3g to 122.4g + 1.3g:

Hence, only the first two digits, hundreds and tens places, are certain. The ones digit is uncertain.

Since, the signficant figures include the certain digits plus one uncertain digit, you should report the number with three significant figures: 2 certain digits + 1 uncertain digit.

The most probable mass of the object would be the mean which is 122.4, which must be rounded to three significant figures, i.e 122 g.

that's what i got you can count the number of atoms

im pretty sure its b