The table shows the rate of inflow of water, in cubic feet per second, as measured every morning at 7:30 AM by the US Army Corps of Engineers at a lake in Georgia. Use the Midpoint Rule to estimate the amount of water that flowed into this lake from July 18th, 2013 at 7:30 AM to July 26th at 7:30 AM.

I've tried evaluating the midpoints like this: (y1+y2)/2 , (y2+y3)/2 , etc. , summing them all and then multiplying them by 60*60*24 (seconds per day). That was incorrect.

I tried using the sum of y2, y4, y6, y8 and then multiplying that by 2*(seconds per day). That also didn't work, so I am currently stumped on this last question on my assignment.

Please help, thanks.