This is a follow-up to www.jiskha.com/questions/1808236/Let-X-denote-the-time-in-hours-needed-to-locate-and-correct-a-problem-in-the-software

Question

So if we take the probability as 0.05 from the left side of the z table, the relavant z value would be -1.64(cause the relevant z value for p(z<=.95)=1.64 and from symmetry)

So as we are finding x such that ,
p(z<=(x-10)/3)=.05

Can we take
-1.64<= (x-10)/3