a.  Baud is determined by substituting into Equation 10:

B=\frac{f_{b}}{N}          (10)

baud =\frac{24,000}{3}=8000

b.  Bandwidth is determined by substituting into Equation 11:

baud =\frac{f_{b}}{N}          (11)

B=\frac{24,000}{3}=8000

c.  Bandwidth efficiency is calculated from Equation 27:

Bη=\frac{\text{transmission bit rate }\,(bps)}{\text{ minimum bandwidth }\,(Hz)}          (27)

Bη=\frac{24,000}{8000}\frac{bps}{Hz}

= 3 bits per second per cycle of bandwidth