A disk-shaped merry-go-round of radius 2.73 meter and mass 165 kilogram rotates freely with an angular speed of 0.621 rev/s. A 55.4 kilogram person running tangential to the rim of the merry-go-round at 3.31 m/s jumps onto its rim and holds on. Before jumping on the merry-go-round, the person was moving in the similar direction as the merry-go-round's rim.
Obtain what the final angular speed of the merry-go-round?