In an examination, 70% of the candidates passed. If the number of candidates who passed was 350, how many failed?

The target total volume is 300 L.

The equation is:

The volume of pure water to add is 230 L. The solute amount remains 250 units.

230 L

Problem (2)

The filling rate is:

$t = \frac{V}{r}$ or equivalently $t = 10V$ (in s, where $V$ in L).

For 24 L:

For 40 L:

For 58 L:

For 247 L:

240 s
400 s
580 s
2470 s