isi 2011

[SHIKHA]

In a sample of households actually invaded by small pox, 70% of
the inhabitants are attacked and 85% had been vaccinated. The
minimum percentage of households (among those vaccinated) that
must have been attacked [Numbers expressed as nearest integer
value] is
(a)    55,     (b)    65,      (c)    30,    (d)    15.  
 

[Ram]

guess the answer is 55 because the percentage should be intersection of those two namely vaccinated and attacked i.e. n(AunionB) = n(A)+n(B)-n(AintersectionB) we know n(A) is 70, n(B) is 85 and total is 100 i.e. union so by applying the formula u will get 55...

[SHIKHA]

no the ans is 65...plz i dont need any guessed ans...i need proper explanation...

[Ram]

I shouldn't have used the word "GUESS" but as for as my knowledge it is 55 only I really cant understand how come it is 65...Somebody plz tell me how it is 65 if it is so???????? lets say there are 100 people out of 100 70 got affected and 85 people are vaccinated then the people those who are affected and got vaccination must be 55....this is my explanation for 55...

[anon_econ]

and 55 people make up 65% of those who had been vaccinated

[Ram]

@Vasudha  Thanks a lot :)