I want this problem to be solved. Can you help me please

Question

15. The time taken in seconds for Ginger's computer to open a specific large documen t is normally distributed with mean 9 and variance 5.91.

a          Find the probability that it takes exactly 5 seconds or more to open the document.

b          Ginger opens the document on her computer on n occasions. The probabili ty that it fails to open in less than exactly 5 seconds on at least one occasion is greater than 0.5. Find the least possible value of n.

Answer 1

mean = 9

variance = 5.91

standard deviation = sqr5.91 = about 2.43

(j5.91-9)/2.43 = z =- 103/81 = about -1.27

use z tables or z calculator on line to find

P(x>-1.27) = area under the normal curve to the right of -1.27