A is correct. Just move the negative sign from in front of the 9 and place it in front of the 4.
Answer:
The percent of error in the measurement is 2%
Step-by-step explanation:
The percent of error associated with a reported measurement is calculate using the formula;

The error associated with a measurement is defined as half of the smallest unit of measurement used. The measurement reported was 2.5. The smallest unit of measurement for this reading is 0.1. The error is thus;
error = 0.1/2 = 0.05
The percent of error is thus;

Answer:
1)0
2)3/8
Step-by-step explanation:
2)total number of participants who are at least 20 years old = 3
Total number of participants= 8