Chapter 5 - Section 5.3 - Assess Your Understanding - Applying the Concepts - Page 285: 16b

$P(at~least~one~bulb~will~burn~out~in~2~years)=0.39423$

The event "at least one bulb will burn out in 2 years" is the complement of "all 100 bulbs will last 2 years". So, we use the Complement Rule (see page 275): $P(at~least~one~bulb~will~burn~out~in~2~years)=$ $1-P(all~100~bulbs~will~last~2~years)=1-0.60577=0.39423$