Question

What will be the number of significant figures in the summation of \(0.153,\; 153.2\) and \(153.2\)?

• A. \(3\)
• B. \(4\)
• C. \(5\)
• D. \(6\)

Hint:

For addition and subtraction:

Look at \textbf{decimal places}, not significant figures
Final answer has the same decimal places as the least precise number

Answer 1

The Correct Option is B

Concept: For addition and subtraction, significant figures are decided by the least number of decimal places, not by the total significant figures of the numbers.
Step 1: Identify decimal places in each number \[ 0.153 \rightarrow 3 \text{ decimal places} \] \[ 153.2 \rightarrow 1 \text{ decimal place} \] \[ 153.2 \rightarrow 1 \text{ decimal place} \] The least number of decimal places is \(\boxed{1}\).
Step 2: Perform the summation \[ 0.153 + 153.2 + 153.2 = 306.553 \]
Step 3: Round off according to least decimal places Since the answer must be reported up to 1 decimal place: \[ 306.553 \approx 306.6 \]
Step 4: Count significant figures in the final answer \[ 306.6 \rightarrow 4 \text{ significant figures} \] Final Answer: \[ \boxed{4} \]