How would you solve for this momentum problem. im totally confused because alot of information is missing?

suppose all the people in the world line up at the equator and start running east at 3.00 m/s relative to the surface of the Earth. By how much does the length of a day increase? ume that the world population is 6.20*10^9, that each person has an average m of 70.0 kg, and that the Earth is a solid geneous sphere.