Problem Solving

13. On a certain scale of intensity, each increment of 10 in magnitude represents a tenfold increase in intensity. On this scale, an intensity corresponding to a magnitude of 165 is how many times an intensity corresponding to a magnitude of 125?
(A) 40
(B) 100
(C) 400
(D) 1,000
(E) 10,000


Hi,
I thought the answer was simply C) but turned out to be E)...... Can anyone help pls?

On a certain scale of intensity, each increment of 10 in magnitude represents a tenfold increase in intensity. On this scale, an intensity corresponding to a magnitude of 165 is how many times an intensity corresponding to a magnitude of 125?
(A) 40
(B) 100
(C) 400
(D) 1,000
(E) 10,000

10 increase in magnitute represents a tenfold increase in intensity
10 increase ---- Factor number by 10
20 increase ----- factor by 10 * Factor by 10
40 increase ----- factor by 10*factor by 10* factor by 10* factor by 10 = 10,000