Answer:
Increasing 20 to 40 is the same as increasing 20 by 20 (or itself), so it is a 100% increase. Decreasing 40 to 20 is the same as decreasing 40 by 1/2 or by 20. So it is a 50% increase.
Step-by-step explanation:
4/3*100^3*π
V = 4/3*π*r^3
= 4/3*π*100^3
≈ 4.18879*10^6
