Each of the two hoses delivers water at a rate of 2 gallons per minute, for a combined total of 2*2=<<2*2=4>>4 gallons of water per minute.
The other two hoses each deliver water at a rate of 3 gallons per minute, for a combined total of 2*3=<<2*3=6>>6 gallons of water per minute.
Thus, all four hoses deliver a combined total of 4+6=<<4+6=10>>10 gallons of water per minute.
With a volume of 15,000 gallons, it would take 15,000/10=<<15000/10=1500>>1500 minutes to fill the pool.
Converting to hours, it will take 1500/60=<<1500/60=25>>25 hours to fill the pool.
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