Solution
For this case we can do the following:
x1 +x2 = 50 (1)
Where:
x1= rate of Florence family
x2= rate of Warren family
And we also know that:
40x1 + 35 x2= 1925 (2)
If we solve from the first equation for x1 we got:
x1= 50 -x2
And replacing in the second equation we got:
40(50-x2) + 35 x2= 1925
2000- 40x2 + 35x2= 1925
2000-1925= 5x2
x2= 75/5 = 15
x1= 50-15= 35
Then the final answer would be:
Florence Family sprinkler: 35 L per hour
Warren Family sprinkler:15 L per hour​