Does the following statement have proper use of significant figures?

The 67th issue of the journal was read by 9,832,456 people.

Determine whether the number is exact or not exact. Note that the number of significant figures of exact numbers is unlimited.

1 ton = 2000 lbs

Select the exact numbers from the following:

(a) the mass of a black ballpen

(b) the average height of buildings around the park

(c) the number of liters in a cubic feet of water

(d) the number of employee in an office

(e) the mass of a soda can

True or False: A decrease in the number of significant figures results in an increase in the level of certainty in the measurement.

The three dartboards shown below are produced by: Person A an expert using their own darts; Person B only played darts a few times; and Person C a new player of darts. For Person B and Person C to have the same results as those in Person A, which of the following should happen?

The true percentage of lead in a sample is 30.56%. Two students measured the percentage for three determinations. Calculate the average percentage for each set of data.

Student 1: 30.55, 30.54, 30.53

Student 2: 30.53, 30.57, 30.56

State which student had a more accurate measurement based on the average.