First thing that should be noted is the relation between Amper and Coulomb. An Ampere is a coulomb of charge flowing past a point in a second. In one hour there are 3600 seconds.
a. The total charge in coulombs is Amperes x time=260 ampere-hours=260*3600=936000 coulombs.
b. The current is charge/time. So, we divide 936000 coulombs with 29 minutes. 29 minutes are 1740 seconds. The current is 576 Amperes.