Additive inverse is what you add to make a number equal to 0. It is the opposite of a number. Example: 4 is the additive inverse of -4. If you add -4 and 4, you get a 0 (-4+4=0). Hope it helped!
You should set this up as a proportion equation. 8.1kg /1hr =x/7hr You would cross multiply here and end up getting the equation... 1x=8.1*7 (x=56.7 kg)
