So obviously there is some information missing from this question (presumably you ran out of space). But the test statistic will be the point estimate minus the mean, divided by the standard error.

Here you have a point estimate (or sample mean) of 13, and a hypothesised mean of 10. So your test statistic will be (13-10) / SEM, where SEM is the standard error of the mean, found by dividing your standard deviation by the square root of your sample size:

SEM = sd / sqrt(n)

So your test statistic will be 3 * sqrt(n) / sd. As soon as you have your standard deviation and sample size available you can plug those in to get the test statistic. Or reply with them here and I'd be happy to calculate it.