Question

The diameter of Mercury is approximately 4.9×103 kilometers. The diameter of Saturn is approximately 1.2×105 kilometers. About how many times greater is the diameter of Saturn than the diameter of Mercury? A 2.4 B 24 C 240 D 2400

Answer 1

As soon as you see "How many times . . .", that usually tells you that finding the answer involves division.  (It certainly does in this one.)

(1.2 x 10⁵) / (4.9 x 10³)  =  

(1.2/4.9) x (10⁵⁻³)  =

0.245 x 10²  =  24.5 times

It looks like  B  is the closest choice.