Proper gating design in metal casting

$$P:$$ Influences the freezing range of the melt
$$Q:$$ Compensates the loss of fluidity of the melt
$$R:$$ Facilitates top feeding of the melt
$$S:$$ Avoids misrun

The height of the down sprue is $$175$$ $$mm$$ and its $$CS$$ area at the base is $$200\,\,m{m^2}.$$ The $$CS$$ area of the horizontal runner is also $$200$$ $$m{m^2}$$. Assuming no losses, indicate the correct choice for the time (seconds) required to fill a mold cavity of volume $${10^6}\,\,m{m^3}.$$ (use $$g=10$$ $$m/{s^2}$$)

Match the cast defect with their cause

According to Chvorinove's rule, the solidification time of a casting is proportional to [Volume/Surface area]ⁿ where $$n=....$$