convert 1/2kg to grams:
[tex] \frac{1}{2} kg = 0.5kg = 500g[/tex]
add the weights times their quantity:
[tex] total \: mass= (8 \times 500) + (12 \times 150)[/tex]
[tex]total \: mass = 4000 + 1800 = 5800g[/tex]
the solution is a total mass of 5800g or 5.8kg
