Add an intersection with a red light times are normally distributed with a mean time of three minutes and a standard deviation of .25 minutes approximately what percent of my lights last between 2.5 and 3.5 minutes

2.5 and 3.5 are two standard deviations from the mean, since 2.5 = 3 - 2(0.25) and 3.5 = 3+2(0.25).

The empirical (68-95-99.7) rule says that approximately 95% of a normal distribution falls within two standard deviations of the mean.

walter needs to make at least 5 more cookies but no more than 40. 5 ≥ x ≥ 40;

step-by-step explanation:

walter has to make a minimum of 20 cookies. he already has 15 cookies made, so he must make 5 more to meet the minimum.

the maximum amount of cookies he can make is 55. he already has 15, so he has to make no more than 40 more cookies to meet the maximum.