Given the following information concerning four stocks,

a) Construct a simple price-weighted average, a value-weighted average, and a geometric average.
b) What is the percentage increase in each average if the stocks' prices become?
1) A: $10, B: $17, C: $13, D: $40
2) A: $10, B: $34, C: $13, D: $20?
c) Why were the percentage changes different in (1) and(2)?

Number of Shares $10 Price Stock A Stock B Stock C Stock D 100,000 50,000 150,000 200,000 13