Answer
$v_A=7700m/s$
$v_B=7503m/s$
Work Step by Step
The earth's radius is $6371km$ and its mass $M=5.98\times10^{24}kg$. The gravitational constant $G=6.67\times10^{-11}Nm^2/kg^2$
Satellite A is $360km$ above the earth's surface. So the distance from satellite A to the earth's center is $r_A=6371+360=6731km=6.73\times10^6m$
Satellite B is $720km$ above the earth's surface. So the distance from satellite B to the earth's center is $r_B=6371+720=7091km=7.09\times10^6m$
The orbital speed of each satellite is
$$v_A=\sqrt{\frac{GM}{r_A}}=7700m/s$$
$$v_B=\sqrt{\frac{GM}{r_B}}=7503m/s$$
