math
posted by Rmz .
A physical fitness association is including the mile run in its secondaryschool fitness test. The time for this event for boys in secondary school is known to posses a normal distribution with a mean of 450 seconds and a standard deviation of 50 seconds. Find the probability that a randomly selected boy in secondaryschool can run the mile in less than 335 seconds.
I do not even know what this is asking...can anyone help??

Z = (x  mean)/SD
Solve for Z and look up Z in table in your stats book called something like "areas under the normal distribution" for the smaller portion.
I hope this helps.