WAITWAITWAIT
In this situation it is much easier to calculate the probability of the event we are looking for (he hits at least one target) by calculating the probability of its complement (he misses every target), and subtracting from 1.
In other words, we can use this strategy:
P(at least one hit)=1-P(miss all 10)
Calculations:
P(at least one hit)
=1-P(miss all 10)
=1-(0.9)^10
≈1-0.349
≈0.65
Answer:
P(at least one hit)≈0.65
oops....