Solve this :    Ans is 4, right.  Coz: 32x/2000 * 100 = 6.4,  Solving this x=4.  Am I right?

Q. Insulin contain 6.4% Sulphur by mass then calculate no. of Sulphur atoms in 1 mole of insulin if molecular mass is 2000 g.

Dear Student,
​
Your answer is correct. see in details:- 

 If  insulin contains 6.4% of S by mass,
then, mass of S in insulin = 6.4% of molecular mass of insulin
                                      = 6.4/100*2000g=128g

Mass of one atom of S in g = 32
So, number of atoms in 128g = 128/32=4 atoms of S.

Regards,​