When We View Video on a Computer, the Analog Video $640 \times 480$

Essay

When we view video on a computer, the analog video is digitized and stored in the frame buffer of the video "frame grabber" card.
Suppose that a video is digitized at (integer) NTSC frame rate, has size $640 \times 480$ pixels, and is stored with a bit depth of 24 bits. We're interested in displaying the captured video.
(a) What must be the minimal bandwidth of the system bus in Mbps when data is moved from the video frame grabber to the memory for video display?
(b) How much storage capacity (in GBytes) is required to store 1 minute of this video?
(c) Explain why you don't see a flicker effect on your workstation screen when displaying this video at NTSC frame rate?