85% of 690 lbs would be 586.5
This cannot be fit into a normal distribution. While the first 7 runners all have times relatively close, the time of the last runner is an outlier, as it is too far from the other data points. The standard deviation is calculated by taking the mean, subtracting each value from the mean, squaring the deviations, adding these, then dividing by the number of data points (7), and taking the square root. This gives an answer of SD = 0.1107.
You’re solving for the volume of the cylinder. so the way you would do this is the area of the base of the cylinder (pi times radius squared) which in this case would be 3.14 x 10^2 which is 314. you would then multiply by h, the height, which here is 10. 314 x 10 is 3140.
1 quart is equal to 4 cups so the answer is B.
