It the fourt day the total is 0.70 because
Day one: .10
Day two: you double it so .20
Day three: you double it again so .40
Day four: you add .30 so .70 is the total
80 divided by 64 then add % to ur answer
So then you will have your percentage to the dogs weight increase
You have to add all the numbers then leave one and subtract it
$6 ? 5+4 =9
9-3 =6
I don't know if this is correct but this is how I would do it