Mr. Sinatra has fenced in a rectangular play area for his new dog (Penny) to play in. Currently, the fenced-in area is 4 times as long as it is wide. However, Mr. Sinatra is considering extending the length by 8 feet and decreasing the width by 2 feet. If the length is increased by 8 feet and the width is decreased by 2 feet, the area will be 240 square feet. What was the area of the original play area? Pls Need the explanation

Assume that females have pulse rates that are normally distributed with a mean of mu equals 72.0 beats per minute and a standard deviation of sigma equals 12.5 beats per minute. complete parts (a) through (c) below. a. if 1 adult female is randomly selected, find the probability that her pulse rate is between 65 beats per minute and 79 beats per minute. the probability is? b. if 16 adult females are randomly selected, find the probability that they have pulse rates with a mean between 65 beats per minute and 79 beats per minute. the probability is? c. why can the normal distribution be used in part (b), even though the sample size does not exceed 30?