observed z ratio

When null hypothesis is population mean 1 = population mean 2 given population s variances and sample sizes and sample means I calculate the SE (standard error=3.51) and DF (degrees of freedom)=40.47 giving me a t=-1.99.
Now, p(t<-1.99)=.027 and p(t>1.99)=.027 so my p-value= 0.054.

Need help explaining what is the z ratio?
What p-value would be associated with the observed z ratio?