An object is taken to a height above the surface of earth at a distance \( \dfrac{5}{4} R \) from the centre of the earth. Where radius of earth, \( R = 6400 \, \text{km} \). The percentage decrease in the weight of the object will be:
\( 36\% \)
\( 50\% \)
\( 64\% \)
\( 25\% \)
