math helpp?

Question

Two rain storms occurred in one week in a certain area. In the first rainstorm 25ML of rain fell per hour, and in the second rainfall 40ML of rain fell per hour. RAin fell that week for a total of 70 hours for a total rainfall of 2200ML. How long was each of the two rainstorms?

Answer 1

Use algebra!!
Let the first rain storm last x hours, and the second rain storm last y hours. We then have:
x + y = 70..................(1)
25x + 40y = 2200.....(2)
Solve the simultaneous equations and you get the answer!
Do not know how to do it? Write (1) as y = 70 - x, and put into (2), we have:
25x + 40(70 - x) = 2200
or 15x = 600 and x = 40, thus y = 30