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Needhelpp101
Medal And Become Fan Rewarded for Correct Info/Answer Please Help Me :D A company installs 5000 light bulbs, each with an average life of 500 hours, standard deviation of 100 hours, and distribution approximated by a normal curve. Find the percentage of bulbs that can be expected to last the period of time. Less than 690 hours. A. 97.06% B. 47.14% C. 97.1% D. 97.2%
first find z =(690-500)/100=1.9 now here we have to find the area under the normal curve for z=1.9
percenatge to last less than 690 hrs is C. 97.1% and that between 500 and above but less than 690 is B. 47.14%