A voice signal sample is stored as one byte Frequency range is 16 Hz to 20 Hz What is the memorysize required to store 4 minutes voice signal?

It's 1920Bytes. As the bandwidth (f2-f1) is 20-16=4Hz. The sampling frequency should be twice the bandwidth (2B). the sampling frequency is 8Hz= 8 samples= 8 cycles/second.

4 minutes=(4*60) =240 Seconds

1sample->1 Byte

1Second->8 Samples

240 Seconds->(240*8) = 1920 Samples