QPSK's practical bandwidth efficiency is around 1.6 b/Hz/s, and each sybol represents 2 bits, so your BW is Baudrate times 1.6 devide by 2. Find bandwidth efficniency for each scheme.
You must specify the pulse shape, a rectangualr pulse differs from RRC, gaussian,..etc. You also need to define the BW (3-dB, Null-to-null, power confinment,...etc). If assume Null-to-null bandwidth for BPSK, then I think the bandwidth is the inverse of the symbol duration (or proportional to this), QPSK will have half of this BW.