Trying to find orbital radius of a satellite

[masterofphys]

Homework Statement

A geostationary satellite in orbit around the Earth has a period identical to that of the Earth's daily rotation; the radius of such an orbit is 4.23 \times 10^4 kilometers. A system of satellites is proposed such that 15 satellites are in orbit at the same radius and each passes over a point fixed on the Earth 14 times per day (the times will be evenly spaced). What will be the orbital radius of each satellite? There will be two such radii; only the smaller will be practical.

Homework Equations

V = $$\sqrt{}Gm(earth)/r$$
T = 2pir/v

The Attempt at a Solution

I tried finding what the current speed would be, but I got a larger value. I'm assuming the speed has to be 14 times what it originally is. I don't know where to begin!

 

[Redbelly98]

Rather than thinking what the speed should be, try to figure out what either the angular speed or the orbital period should be.