Gimana cara ngitungnya....??

wc = 60 rpm
wc = 60 . 2л rad : 60 s
wc = 2л rad/s

vb = vc
wb . Rb = wc . Rc
wb . 15 cm = 2л rad/s . 40 cm
wb = 16/3 л rad/s

va = vb
wa . Ra = wb . Rb
wa . 25 cm = 16/3 л rad/s . 15 cm
wa = 16/5 л rad/s
wa = 3,2 л rad/s. jawabannya= {C}