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Two rainstorms occurred in one week in a certain area. The first storm lasted hours, and the second storm lasted hours, for a total of rain. What was the rate of rainfall for each of the two storms if the sum of the two rates was per hour?

2006-07-28 21:28:58 · 8 answers · asked by planetlopez 1 in Science & Mathematics Mathematics

Two rainstorms occurred in one week in a certain area. The first storm lasted 20 hours, and the second storm lasted 40 hours, for a total 1400 mL of rain. What was the rate of rainfall for each of the two storms if the sum of the two rates was 50 mL per hour?

2006-07-28 21:32:07 · update #1

8 answers

X- RATE OF STORM1
Y- RATE OF STORM2

x+y=50
20x+40y=1400
x=50-y
1000-20y+40y=1400

20y=400
y=20 so x=30

So first storm had a rate of 30 mililiters per hour
second had 20 mililiters per hour

2006-07-28 21:39:37 · answer #1 · answered by Roxi 4 · 0 0

(1) x / 20 = rate of rainfall for the first storm
(2) x + y = 1400
(3) x = 1400 - y

sub (3) into (1)
(1400 - y) / 20 = rate of rainfall for the first storm

(1400 - y) / 20) + (y/40) = 50

now isolate y:
40 * (((1400 - y) / 20) + (y/40) = 40 * 50
2800 - 2y + y = 2000
-y = 2000 - 2800
(4) y = 800 mL

sub (4) into (2)
x + 800 = 1400
x = 600

CHECK:
x/20 + y/40 ?= 50
600/20 + 800/40 = 50
30 + 20 = 50 mL/h

Hope that helps.

2006-07-29 04:57:11 · answer #2 · answered by guitarmensa 1 · 0 0

Try setting eqn to zer0

20x+40(50-x)-1400=0
-------
20x=2000 - 40x-1400=0
-20x+600=0
x=30 mL
plug that into 20 x+40y= 1400

600+40y=800
y=20mL

2006-07-29 04:49:51 · answer #3 · answered by Lily 2 · 0 0

I still think there's something missing, but you can think of it the physics way {use units}.

Total time it rained = 40h + 20h = 60h

Total rainfall = 1400mL

Rate of rainfall {mL/h} = ?

2006-07-29 04:42:35 · answer #4 · answered by adder_86 2 · 0 0

let x= rate of first storm
let y = rate of second storm
20(x)+40(y)=1400
x+y=50
.....
-20y+1000+40y=1400
20y=400
y=20
x=30

2006-07-29 05:00:05 · answer #5 · answered by sphinx 4 · 0 0

Insufficient data. Difficult to answer.

2006-07-29 04:31:59 · answer #6 · answered by sharanan 2 · 0 0

wel i hope some1 really helps u out of dis rain.............. ;-)

2006-07-29 04:40:13 · answer #7 · answered by ana 2 · 0 0

WTF I got as far as naming variables then i said F uc k this

2006-07-29 04:33:12 · answer #8 · answered by yankovicfan6 3 · 0 0

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