The lifetime of a certain type of battery is normally distributed with mean value 15 hours and standard deviation 1 hour. there are four batteries in a package. what lifetime value is such that the total lifetime of all batteries in a package exceeds that value for only 5% of all packages? (round your answer to two decimal places.) hours

33.68 hours

Step-by-step explanation:

The lifetime of a certain type of battery is normally distributed with mean value 15 hours and standard deviation 1 hour then

The lifetime of a battery package consisted of 4 batteries is normally distributed with mean value 60(15×4) hours and standard deviation 16 (1 × ) hour

If the total lifetime of all batteries in a package exceeds lifetime value for only 5% of all packages then P(z<Z)=0.05 where

From z-table we can conclude that Z=-1.645

Z is also calculated as:

Z=-1.645= where

Solving the equation for X we get X=33.68

really your just stupid if you don't know this

step-by-step explanation: