1,000 light bulbs with a mean life of 120 days are installed in a newfactory. Their length of life is normally distributed with standarddeviation 20 days. (1) How many bulbs will expire in less than 90days? (ii) If it is decided to replace all the bulbs together, whatintervals should be allowed between replacements if not more than10 per cent should expire before replacement ?

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Answered: 1,000 light bulbs with a mean life of…

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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