The heart pumps 750*24/9=2000 gallons, and the kidney pumps 100*24/6=400 gallons. This is a difference of 2000-400=1600 gallons.
This is what I learned:
D = Divide
M = Multiply
S = Subtract
B = Bring down
C= Check
D= Dad
M= Mom
S= Sister
B= Brother
C= Cousin
Hope this helped you! :)