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.
