Chapter 19, Problem 19.93SP

Given the following half-reactions and E^o values,
$M{n}^{3+}(aq)+e^{-}\to M{n}^{2+}(aq)$ $E^o=1.54\text{ V}$
$Mn{O}_2(s)+4H+(aq)+e^{-}\to M{n}^{3+}(aq)+2H_{2}O(l)$ $E^o=0.95\text{ V}$
write a balanced equation for the formation of $M{n}^{2+}$ and MnO₂ from $M{n}^{3+}$ , and calculate the value of $E^o$ for this reaction. Is the reaction spontaneous under standard-state conditions?