What does the sales discount $2/10,$ n$/30$ mean?

You can take a $10\%$ discount if you pay within $2$ days, or a $30\%$ discount if you pay today.

You can take a $2\%$ discount if you pay within $10$ days, or the full amount is due within $30$ days.

For every day the bill is overdue past $10$ days, you will be charged $2\%$ interest.

You can take a $10\%$ discount if you pay within $2$ days, or the full amount is due within $30$ days.