Probability for Difference in Sample Means

A researcher compares two treatments. The two populations of reaction times are independent and approximately normally distributed with standard deviations of $\sigma_1 = 0.15$ seconds and $\sigma_2 = 0.20$ seconds, respectively. If independent random samples of size $n_1 = 25$ and $n_2 = 36$ are selected, what is the probability that the observed difference in sample means, $\bar{x}_1 - \bar{x}_2$, is within 0.05 seconds of the true difference in population means, $\mu_1 - \mu_2$?