physic question ,anyone can find the Solution for this question plz

The sudden movement of a fault in the Earth’s crust sends out seismic waves of different types. Consider a P wave which travels straight downwards from an earthquake focus located very close to the Earth’s surface and passes through the Centre of the Earth before emerging at an epicentral angle of 180°.

i-How long does this journey take, and what distance is covered? (Show all your working.)

ii-Calculate the average speed of the wave on its journey, giving your answer in units of km s−1 to two significant figures. (Show all your working.)

iii-In which region of the Earth do P waves travel the fastest and in which region do they travel slowest, and what type(s) of material is/are present in these regions? ( one or two sentences.)