Answer:
Let U1 and U2 be the gravitational potential energy of the first and second stone respectively.
U1 is given by:
[tex]U_1 = (m)gh\\[/tex]
and U2 is given by:
[tex]U_2 = (4m)gh[/tex]
therefore, comparing the energies we have:
[tex]\frac{U_2}{U_1} = \frac{(4m)gh}{(m)gh}= 4[/tex]
therefore:
[tex]U_2=4U_1[/tex]