Answer:
volume of sphere=4/3 π4³=256/3π ft²
The time needed at 2 meters per second for both rounds would be 100/2 s or 50 seconds. For the first lane he already used 50/1.5 -> 33.33 seconds, so he would need to cover the other 50 meters in exactly 16.67. 50m divided by the 16.67 seconds he has left means he has to swim at a speed of 3 meters per second.
Answer:
475.
Step-by-step explanation:
We have been given that for a normal distribution with μ=500 and σ=100. We are asked to find the minimum score that is necessary to be in the top 60% of the distribution.
We will use z-score formula and normal distribution table to solve our given problem.

Top 60% means greater than 40%.
Let us find z-score corresponding to normal score to 40% or 0.40.
Using normal distribution table, we got a z-score of
.
Upon substituting our given values in z-score formula, we will get:





Therefore, the minimum score necessary to be in the top 60% of the distribution is 475.