I need help with this..I have 50 of these problems so if you can show me how to calculate this one I can do the rest myself...Thanks!

Let s(t)=√t

a.Find the average rate of change of s(t) with respect to t as t changes from t=1 to t=1/4

b.Use calculus to find the instantaneous rate of change of s(t) at t=1 and compare with average rate found in part(a).