Ok, the middle part of your distribution is considered as normal, and this represents 80% of the whole number of systems.

You are asked to find the value of X in my diagram. (Note: I made a mistake and the X should be on the left instead. Sorry about that)

For the last part, find the probability that it takes longer than 60 seconds, that is, find P(X > 60)

Then, find the probability is less than 10% (that is 0.1) then this system is considered as slow. If not, then it's considered as normal.

Post what you come up with!