Question

Express the final answer to the proper number of significant figures: \[ 18.0 + 11.515 + 13.2 = \ldots \]

• A. 42.715
• B. 42.7
• C. 42.72
• D. 42.7150

Hint:

When adding or subtracting, always round your result to the least number of decimal places. This rule applies to significant figures in addition or subtraction.

Answer 1

The Correct Option is B

When adding or subtracting numbers, the result should be rounded to the least number of decimal places. Let’s analyze the numbers: - 18.0 has 1 decimal place. - 11.515 has 3 decimal places. - 13.2 has 1 decimal place. The least number of decimal places is 1, so the sum should be rounded to 1 decimal place: \[ 18.0 + 11.515 + 13.2 = 42.715 \] Rounding to 1 decimal place, the final result is 42.7.