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?
(ii) it will last more than 9000 km?
(iii) it will need to be replaced after it has covered somewhere between 4000 km and 14000 km?

Explanation

Probability that it will need to be replaced before it has covered400km=`20/1000=0.02`
probability that it will last more than 9000km=`(325+445)/1000=770/1000=0.77`
Probability that it will need to be replaced after it has covered somewhere between 4000 km and 14000 km=`(210+325)/1000=535/1000=0.535`