Answer:
570 m³
Step-by-step explanation:
The volume of water is the product of flow rate of water and the time taken. We are to get the volume of water used between 6 am and 9 am, that is for 3 hours (9 - 6).
We are given the flow rate at 6 am and the flow rate at 9 am, but this flow rate changes between 6 am and 9 am. To get the estimate of the water used, Let us assume that it flows at the same flow rate as it was at 6 am throughout, hence:
[tex]V_L= 100 m^3/h * 3h=300\ m^3[/tex]
Also, let us assume that it flows at the same flow rate as it was at 9 am throughout, hence:
[tex]V_R= 280 m^3/h * 3h=840\ m^3[/tex]
To get the best estimate of the total volume, let us find the average of the two values, hence:
[tex]Volume=\frac{V_L+V_R}{2} =\frac{300+840}{2}=570\ m^3[/tex]