Answer
$10$ tablets
Work Step by Step
Determine vitamin C per tablet:
$500.0\text{ mg}\times 0.20=100.0\text{ mg}$ vitamin C per tablet
Calculate number of tablets needed:
$\frac{1000\text{ mg}}{100.0\text{ mg/tablet}}=10\text{ tablets}$
You need $10$ tablets to get a $1.00$ g dose of vitamin C.
