Answer: Whoever read the 15 pages before read the most.
Step-by-step explanation:
An exercise ball, also known as a yoga ball, is a ball constructed of soft elastic with a diameter of approximately 35 to 85 centimeters (14 to 34 inches) and filled with air. The air pressure is changed by removing a valve stem and either filling with air or letting the ball deflate. It is most often used in physical therapy, athletic training and exercise. It can also be used for weight training. The ball, while often referred to as a Swiss ball, is also known by a number of different names, including balance ball, birth ball, body ball, ball, fitness ball, gym ball, gymnastic ball, physio ball, pilates ball, naval mine, Pezzi ball, stability ball, Swedish ball, or therapy ball.
Answer:
0.0359
Step-by-step explanation:
Data provided:
mean values of three independent times are 15, 30, and 20 minutes
the standard deviations are 2, 1, and 1.6 minutes
Now,
New Mean = 15 + 30 + 25 = 65
Variance = ( standard deviation )²
or
Variance = 2² + 1² + 1.6² = 7.56
therefore,
Standard deviation = √variance
or
Standard deviation = 2.75
Thus,
Z-value = 
or
Z-value = - 1.81
from the Z-table
the Probability of Z ≤ -1.81 = 0.0359
