.50x +4001 = 6,000, solve for x
x =3,998 Kg. Replace 4001 above with 3,998,
x =4,004 Kg. Replace 3,998 above with 4,004.......and so on.
x=3,992 Kg.
x=4,016 Kg
x=3,968 Kg
x=4,064 Kg
x=3,872 Kg
x=4,256 Kg
x=3,488 Kg
x=5,024 Kg
x=1,952 Kg
x=8,096 Kg. These are Alan's numbers. However, the last elephant's weight can be any number above 5,024 Kg, since it is the heaviest and is excluded from the rule.
There are only two unique solutions. That is, with the initial weight of either 4,000 or 4,001 Kg. The initial weight of 3,999 kg, gives the weight of the 12th elephant as 6,048 Kg. The initial weight of 4,002 Kg gives the weight of the 11th elephant as 6,048 Kg.
