Let the first term be \(a\), difference \(d\). Then \[117=\frac92(2a+8d)\quad\Longrightarrow\quad a+4d=13.\] The next four terms are terms 10 to 13, so \[91=\frac42((a+9d)+(a+12d))\quad\Longrightarrow\quad2a+21d=45.5.\] Subtract \(2a+8d=26\), giving \(13d=19.5\), hence \(\boxed{d=1.5,a=7}\).