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Example 6 - A tyre manufacturing company kept a record - Grouped frequency

Example 6 - Chapter 15 Class 9 Probability - Part 2

Example 6 - Chapter 15 Class 9 Probability - Part 3


Transcript

Example 6 A tyre manufacturing company kept a record of the distance covered before a tyre needed to be replaced. The table shows the results of 1000 cases. If you buy a tyre of this company, what is the probability that : (i) it will need to be replaced before it has covered 4000 km? Total number of trials = 1000. Frequency of tyre that needs to be replaced before it covers 4000 km = 20. So, P (tyre to be replaced before it covers 4000 km) = 20/1000 = 0.02 Example 6 If you buy a tyre of this company, what is the probability that : (ii) it will last more than 9000 km? Total number of trials = 1000. Frequency of tyre that it will last more than 9000 km = Frequency of tyre that will last 9001 to 14000 km + Frequency of tyre that will last more than 14000 km = 325 + 445 = 770 So, P(tyre will last more than 9000 km) = 770/1000 = 0.77 Example 6 If you buy a tyre of this company, what is the probability that : (iii) it will need to be replaced after it has covered somewhere between 4000 km and 14000 km? Total number of trials = 1000. Frequency of tyre that requires replacement b/w 4000 & 14000 km = Frequency of tyre that will last b/w 4000 to 9000 km + Frequency of tyre that will last b/w 4001 to 14000 km = 210 + 325 = 535 P(tyre requiring replacement between 4000 km and 14000 km) = 535/1000 = 0.535

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Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.