Thallium-208 has a half-life of 3.053 min. How long does it take for 120 g to decay to 7.50?

what is the question here. i think you messed up.

weight of any object is given by

w = m*g

where m is mass of the object and g is the acceleration due to gravity.

for earth the value of g is 9.8 m/s^2 so

w=117.6 n m=12 g=?

117.6=12g => g=9.8 m/s^2

which is the force of gravity on earth.