we need to compare 8x10^7 with 2x10^4. So we need to divide 8x10^7 between 2x10^4.
[tex]\frac{8\times10^7}{2\times10^4}=4\times10^{7-4}=4\times10^3=4000[/tex]Therefore 8x10^7 is 4000 times larger than 2x10^4
ANSWER
A: 8 · 10^7 is 4,000 times larger than 2 · 10^4.