To answer this question, you need to know the molecular weight of zinc so you can determine how many mol zinc you have. Zinc molecular weight is 65.38gram/mol. Then the calculation would be: 48.3gram/(65.38gram/mol)= 0.74 mol
Since you are asked the amount of atom, you need to multiply the unit in mole with Avogadro number. The calculation should be: 0.74 * 6.02 * 10^23= 4.45* 10^23 molecules