a) speed of wave pulse= distance/time=90.0cm/1.69=53.3 cm/s(3 s.f.)=0.533 m/s(3 s.f.)
b)By reducing the tension, the wave pulse will become slower. Changing the tension does not change the width of the pulse so, it remains the same but the speed decreases as the tension is decreased.
Done By Soe Yan Nuang aka Norman and Jun Hao