Question

A tyre manufacturing company kept a record of the distance covered before a tyre to be

replaced. Following table shows the results of 100 cases. [5]

Distance in km Less than 400 400 to 900 900 to 1400 More than 1400

Number of tyres 210 325 385 80

If you buy a tyre of this company, what is the probability that:

(i) it will need to be replaced before it has covered 400 km?

(ii) it will last more than 900 kin?

(iii) it will need to be replaced after it has covered somewhere between 400 km and 1400 km?

(iv) it will not need to be replaced at all?

(v) It will need to be replaced?​

Answer 1

Answer:

Step-by-step explanation:(i) 20 tyres need to be replaced before 4000 km out of 1000 tyres.

probability that the tyre needs to be replaced before covering 4000 km = 20/1000 = 0.02 or 2%

(ii) tyres replaced after 9000 km = 325+445 = 770 tyres out of 1000

probability = 770/1000 = 0.77 or 77%

(iii) tyres replaced between 4000 and 14000 km = 325+210+20 = 555 tyres out of 1000

probability = 555/1000 = 0.555 or 55.5%