Two rainstorms occurred in one week in a certain area. In the first storm 25ml of rain fell per hour, and in the second storm 35 ml of rain fell per hour. Rain fell that week for a total of 60 hours for a total rainfall of 1900 ml. How long each stor?

Had the first storm been the only storm, (60 hr)*(25 ml/hr) = 1500 ml would have fallen. The second storm added 10 ml to the total for each hour it raged.
  (1900 ml - 1500 ml)/(10 ml/hr) = 40 hr
The first storm lasted 20 hours, the second storm lasted 40 hours.

---

1.9 meters of rain in a week will tax the capacity of most drainage systems. Pack the valuables and head for high ground. Beware of mudslides.