For the FIRST (top) chart:
1) If the area of the big circle represents 1,000 observations, how many observations does the second-biggest circle represent?
2) If the area of the second-biggest circle represents as many observations as you just said, how many observations does the third-biggest circle represent?
For the SECOND (bottom) chart :
3) If the area of the big circle represents 1,000 observations, how many observations does the second-biggest circle represent?
4) If the area of the second-biggest circle represents as many observations as you just said, how many observations does the third-biggest circle represent?