Note that in performing division and multiplication with significant figure, the number of significant figures in the answer will follow the least number of significant figures from the given.
4 x 10^5 has 1 significant figure
6 x 10^23 has 1 significant figure
1.2 x 10^2 has 2 significant figures
So the answer should be in 1 significant figure only.
Simplifying the expression :
[tex]\begin{gathered} \frac{(4\times10^5)(6\times10^{23})}{1.2\times10^2}=\frac{4\times6}{1.2}\times10^{5+23-2} \\ \Rightarrow20\times10^{26} \end{gathered}[/tex]
But 20 has 2 significant figures, so moving the decimal point to the left will give us :
[tex]2\times10^{27}[/tex]
The answer is C. 2 x 10^27
