Question

How many times larger is 4 x 1012 than 8 x 107? A) 2 x 104 B) 2 x 105 C) 5 x 104 D) 5 x 105

Answer 1

Answer: The correct option is C.

Explanation:

We have to find that how many times larger is $4\times (10)^{12}$ than $8\times (10)^{7}$.

Let $4\times (10)^{12}$ is k times larger than $8\times (10)^{7}$.

$4\times (10)^{12}=k8\times (10)^{7}$

$k=\frac{4\times (10)^{12}}{8\times (10)^{7}}$

$k=\frac{0.5\times (10)^{12}}{(10)^{7}}$

$k=\frac{5\times (10)^{12}}{10\times(10)^{7}}$

Use exponent rule $a^m\times a^n=a^{m+n}$

$k=\frac{5\times (10)^{12}}{(10)^{8}}$

Use exponent rule $\frac{a^m}{a^n}=a^{m-n}$

$k=5\times (10)^{12-8}$

$k=5\times (10)^{4}$

Therefore, the option C is correct.

Answer 2

4 x 101^2
------------- = 0.5 x 10^5 = 5 x 10^4
8 x 10^7

answer is C.

C) 5 x 10^4