T-test and Z-test won't work

#1
How can I solve this problem?

X brand of batterys have a mean charge lasting time of 90 minutes and a standard deviation is 35 minutes but are not normally distributed.

What is the probability that a randomly selected battery lasts more than 100 minutes?

I can't use a t-test for only one battery because there are 0 degrees of freedom. I can't use a z-test because the population is not normally distributed. If anyone could explaine how to solve this problem I would really appreciate it.
 

JohnM

TS Contributor
#2
This can't be answered unless you know the underlying probability distribution of the battery life.

You can't even use Chebyshev's Theorem (i.e., at least 1- (1/k^2) percent of the data lies within k standard deviations) because 100 is less than 1 standard deviation away from the mean of 90.