Give the correct number of significant figures to the problem below.2.4 x 10^-4 + 3.1 x 10^-2 = A)5.5 x 10^-6 B)5.5 x 10^-8 C)5.5 x 10^-4 D) 3.1 x 10^-2 E) 2.4 x 10^-4

Question

Quizplus · Accepted Answer

When adding or subtracting numbers with different powers of 10, we need to adjust one or both of the numbers to have the same power of 10. In this case, we can adjust the first number to be 0.024 x 10^-2 and the second number to be 0.031 x 10^-2. When we add these two numbers, we get 0.055 x 10^-2, which can be written as 5.5 x 10^-3 in scientific notation. The number 5.5 has two significant figures, and the power of 10 (-3) does not affect the significant figures, so the final answer has two significant figures. Therefore, the best choice is D.

Give the Correct Number of Significant Figures to the Problem