Question

2.1x 10^8 is how many times the value of 4.2 x 10^2?

A 5.0 x 10^5
B 5.0 x 10^6
C 2.1 x 10^5
D 2.1 x 10^6

Answer 1

Explanation:

If you want to find out how many times larger something is than something else, you have to divide. We will set up a problem that looks like this:

`(2.1*10^8)/(4.2*10^2)`

Diving 2.1 by 4.2 gives us .5; to divide the exponents, we remember that if we divide like bases we have to subtract the exponents. 10 is our base in both cases, so 8 - 2 gives us 6, resulting in:

`.5*10^6`

However, this isn't in scientific notation. We need to move the decimal one more place to the right, which in trn reduces the exponent by 1:

`5*10^5`