Three sprinters A, B, and C had to sprint from points P to Q, which are 55 meters apart, and back again (starting in that order). The time interval between their starting times was 5 seconds each. C started 10 seconds after A, while B started 5 seconds after A. They passed a certain point R, which is somewhere between P and Q, simultaneously (none of them having reached point Q yet). Having reached Q and reversed the direction, the third sprinter met the second one 9m short of Q and met the first sprinter 15m short of Q.

Find the speed of the three sprinters.