The answer is 8.325 m/s. you take 3 loops divided by 2--> 3/2 equals 1.5m. Then you divide 1.5m into 5 meters of slinky--> 5m/1.5 = 3.33m. Then because of the equation of speed, V(speed)=wavelength x frequency. Our wavelength is 3.33m, and the frequency is the HZ (remember cycles per second?). so therefore, speed= 3.33m * 2.5 HZ. The answer then becomes 8.325 m/s.