please solve this question fastly​

total no of neutrons =

MOLE X NA X 8

MOLE =7 X10^-3/14 =0.5 X10^-3

neutrons = 5x10^-4x6x10^23 x8

=240 x10^23

=2.4x 10^25 neutrons.

mass of neutrons = 2.4x 10^25 X 1.66 x10-^24 =3.98x10 =39.8gm

aprox =40.gm