Answer:
Distance of blackhole from center of earth 2000 Re
Explanation:
we have mass of earth [tex]= Me = 5.972 \times 10^{24} kg[/tex]
Mass of black hole [tex]Mb = 12 \times M_{sun} = 12 \times 1.989 \times 10^{30} kg = 23.868 \times 10^{30} kg[/tex]
Object start to lift in air when net force on them becomes zero
[tex]\frac{ G Mb m}{x^2} = \frac{GM_{sun} m}{Re^2}[/tex]
[tex]\frac{MB}{x^2} = \frac{M_E}{R_E^2}[/tex]
[tex]x = \sqrt{\frac{Mb}{M_E}} R_E [/tex]
[tex]x = \sqrt{\frac{23.868 \times 10^{30}}{5.972 \times 10^{24}}} R_E[/tex]
[tex]x = 1.99 \times 10^{3} Re[/tex]
x = 1999.16 Re
So, distance of blackhole from center of earth will be = x+ Re
   = 1999.16 Re + Re = 2000.16 Re