There are 500 packets in a large box and each packet contains 4 electric devices in it. On testing, at the time of packing, it was noted that there are some faulty pieces in the packets. The data is as given below :
No of faulty devices in a packet01234Total number of packetsNumber of packets300100503020500
(i) If a buyer will only tolerate the maximum of one faulty piece in a packet, what is the probability that a packet will be rejected by him?
(ii) Another buyer will only take packets with all the pieces functional. What is the probability that a packet will be rejected? [4 MARKS]
Concept: I Mark
Solution: 1.5 Marks each
Packets with more than one defective piece = 50 + 30 + 20 = 100
(i) Probability that the first buyer will reject a packet
=100500=0.2
Packets with no defective piece = 300
Packets with at least 1 defective piece = 500-300 = 200
(ii) Probability that the second buyer will reject a packet = =200500=0.4