Answer:
79.77 minutes
Step-by-step explanation:
first you have to find out how many liters the pipes drain per minute
pipe 1: 585000/135=4333.33 lpm
pipe 2:585000/195=3000 lpm
p 1 and 2: 7333.33 lpm
now divide the lpm of both pipes by the amount in the pool to find your answer
585000/7333.33=79.77 minutes