\( \definecolor{colordef}{RGB}{249,49,84} \definecolor{colorprop}{RGB}{18,102,241} \)
Suppose \(X\) represents the battery life (in hours) of a new smartphone model, and it follows a normal distribution with a mean of 12 hours and a standard deviation of 2 hours. The manufacturer sets a warranty replacement time such that 80\(\pourcent\) of phones last at least this long before needing a recharge. Find this time (i.e., the 20th percentile, since it’s the lower tail). Round your answer to one decimal place.
\(x \approx\)