Its 480;

let total who filled the questionnaire is x
120 dint enjoy then x-120 enjoyed.

also 3x/4= both who enjoyed and understood

total = x-120+x-120- 3x/4 + 120 = x
=> 5x/4 - 120 = x
=> x/4 = 120
=> x = 480

Hope this helps..!!

Its 480;

let total who filled the questionnaire is x
120 dint enjoy then x-120 enjoyed.

also 3x/4= both who enjoyed and understood

total = x-120+x-120- 3x/4 + 120 = x
=> 5x/4 - 120 = x
=> x/4 = 120
=> x = 480

Hope this helps..!!

after posting the question i realized that 'All' in this line is the most important word,

all 120 visitors who did not enjoy the painting, also did not feel they had understood the painting

which i missed whilst trying to solve initially!

thanks anyway!

Honestly, I did not understand the following step of killer 1387:

total = x-120+x-120- 3x/4 + 120 = x


But anyways I got the solution as E as follows:

Let me give you a precise equation:

There are 2 circles representing equal number let say a = b

so the equation would be:

a + a - 3/4 x + 120 = x {let the total people who filled out the questionaire be x}

solving the above, we get

2a + 120 = 7/4x (hence two variables)

therefore, 8a - 7x = -480

Now try putting all the values from A to E and see what the answer of a comes out to be...

For all the options except for E, 'a' turns out to be less than the common between both of them i.e a as well as b.

That is never possible in Sets. Suppose in AUB = n(A) + n(B) - n(A intersection B)

In this n(A) or n(B) can never be less than n(A intersection B)...

The same thing is happening in the above example and hence I chose the answer as E.

I really do not know how killer 1387 solved the equation having 2 unknown variables i.e x and a

Hope this post really helped you guyzzzzz!!!

[email protected] wrote:Honestly, I did not understand the following step of killer 1387:

total = x-120+x-120- 3x/4 + 120 = x

I proceeded by using two circle that you talked of.
question does says 120 of x doesnt enjoy /understand this means x-120 did enjoyed = no. of people who understand.
Also its given the common guys are = 3x/4

hence total would be
(x-120)+(x-120)- 3x/4 + 120 and this is x.(Note: i have subtracted 3x/4 because its common in both fields)

Hope this clears..!!