Question 976694
Your weight is a measure of the attractive force between you and the Earth and is inversely proportional to the square of your distance from the center of the Earth. 
{{{W=k/r^2}}}
{{{Wr^2=k}}}
{{{W[1]*r[1]^2=W[2]*r[2]^2}}}
{{{W[2]=W[1]*(r[1]/r[2])^2}}}
{{{W[2]=160(4000/8000)^2}}}
{{{W[2]=160(1/4)}}}
{{{W[2]=40}}}{{{lbs}}}