The grams of beryllium that are in 147 g of the mineral is calculated as follows
find the moles of the mineral
that is = mass/molar mass (537g/mol)
= 147g/537g/mol = 0.274 moles
mass of Be = moles x molar mass of Be x 3 since there is 3 Be atom in the mineral
= 0.274 mol x3 x 9 g/mol = 7.4 g