Geology please help me!!?

(Q004) Part 4.a. Observations of modern mountain belts suggest that ranges erode at rates of 2 mm per 10 years. At this rate, how long would it take to erode the Himalayas down to sea level?
 a. 4.4 × 104 yr
 b. 4.4 × 107 yr
 c. 4.4 × 106 yr
 d. 4.4 × 103 yr

Anonymous2021-01-27T17:46:28Z

The math is quite easy, you have the distance travelled and the time it took.

Its no different than calculating how fast you drove from one place to another if you travelled x kilometers in y hours.