Answer: 51,200 litres per second
Explanation:
Assume that the rate before the rain is denoted as x.
This would mean that 74,240 liters per second is an increase of 45% over the value of x.
In formula form therefore this is:
74,240 = x + (x * 45%)
74,240 = x + 0.45x
74,240 = 1.45x
x = 74,240 / 1.45
x = 51,200 litres per second