Hm maybe look up the name of the document and put pdf answers
87 24/25.......24/25 = 0.96......answer is 87.96
224 7/10....7/10 = 0.7....answer is 224.7
686 49/50...49/50 = 0.98...answer is 686.98
x = number of hours
want to find probability (P) x >= 13
x is N(14,1) transform to N(0,1) using z = (x - mean) / standard deviation so can look up probability using standard normal probability table.
P(x >= 13) = P( z > (13 - 14)/1) = P(z > -1) = 1 - P(z < -1) = 1 - 0.1587 = 0.8413
To convert that to percentage, multiply 100, to get 84.13%
If you have snap you can use that just hold down on screen your problem
