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set theory

by Vookeh dyzynah » Tue Apr 24, 2012 1:15 am
In a survey it was reported thatb 400 people owned fiet cars and 200 owned ambassador cars. 50 owned both fiet & ambassador cars. Determine the no. of cars that were surveyed?

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by LalaB » Tue Apr 24, 2012 1:25 am
400+200-50=550
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by Mr Smith » Tue Apr 24, 2012 2:49 am
Set A is of people who own ambassadors.
n(A) = 200
Set F is of people who on fiats
n(F) = 400

It is given that n(A Intersection F) = 50

The total number of people is n(A union F)
And we know that n(A union F) = n(A) + n(F) - n(A intersection F)
=200 + 400-50
= 550

Another way to look at it is when we add the number of people who own ambassadors(200) to the number of people who own fiats(400) we are counting the people who own both twice. Hence we subtract the number of people who own both once
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by [email protected] » Tue Apr 24, 2012 4:58 am
Vookeh dyzynah

Dude there is a formula in Sets i.e

n(A) + n(B) - n(A intersection B) = n(AUB) i.e the total people surveyed...

When you put the values of the question in the above formula, you get the answer as 550

Intersection is referred to as common between both parameters i.e A and B.

You are new to this site right? Welcome to BTG, and I would recommend you to go through some basic concepts before solving sums...

In case of any queries, you could always PM me...

Hope I helped you, Thank You.
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