The weight of an African elephant is 6x10^6 grams; the weight of a tiger is 3x10^5 grams. How many times heavier is the elephant than the tiger?

The answer would be 20 times longer.

So that means

elephant = x times tiger

6 times 10^6=x times 3 times 10^5

divide both sides by (3 times 10^5)

remember that (x^m) / (x^n) = x^ (m-n)

so

(6 times 10^6) / (3 times 10^5) = x

(6/3) times (10^6) / (10^5) = x

2 times 10^1=x

2 times 10=x

that would be 2 times 10^1 or 20 times