Although television HDTV converters are tested before they are placed in the installer's truck, the installer knows that 20 percent of them still won't work properly. The driver must install eight converters today in an apartment building. (a) Ten converters are placed in the truck. What is the probability that the driver will have enough working converters? (Round your answer to 4 decimal places.)

Probability .6778

(b) How many boxes should the driver load to ensure a 95 percent probability of having enough working converters?

Number of boxes ???