Now that we have the function (referencing the previous problem):

q(t)=72t+54t4+6\displaystyle {q}{\left({t}\right)}=\frac{{7}}{{2}}{t}+\frac{{5}}{{4}}{t}^{{{4}}}+{6}

Find the charge after 3 seconds.

q(3)=\displaystyle {q}{\left({3}\right)}=   amperes