A manufactory company manufactures flash drivers and their products include: 1GB (10%), 2GB (10%), 4GB (20%), 8GB (30%), 16GB (20%) and 32GB (10%); in addition, there're four different colors for all the flash drivers: green, black, yellow, red and they're produced equally in amount for each color. If you randomly choose a flash driver for inspection:
If the defect rate for flash drivers is 0.5% and you randomly select four of them for inspection:
a) Determine the probability that none of them has a defect?
b) Find out the probability that all four have a defect?
c) Compute the probability that the first one you select has a defect?
d) Compute the probability that either one of four you select has a defect?