Note:
The equatorial diameter of the earth is 12,756 km.
Therefore the equatorial radius is
r = 12756/2 = 6378 km.
The angular velocity of the earth is
ω = (2π radians)/(24 hours) = 0.2618 rad/h
The tangential velocity of a person at the equator is
v = rω
= (6378 km)*( 0.2618 rad/h)
= 1670 km/h
Answer: 1670 km/h