Greg Quant Concept Series: Possible Mistake

[user1682]

Hi everyone,

Topic: Overlapping Sets and Multiplication Principle & Permutations Combinations
Sub topic: Overlapping sets
Link to video: Last question in the video

Here in this question, you can see that Greg uses the percentage values in the variables for ‘a’ through ‘f’ and sums them up to 150 (which is the number, not a percentage)

My doubt is, shouldn’t we have calculated a = (0.60 *150), b = (0.30 * 150) … and so on before proceeding to solve the question?

So the solution would be

let d+e+f = Z
a=0.60 150 = 90, b = 0.50 150 = 75, c = .30 * 150 = 45
a+b+c - Z = 150 - (5+5)
Z = (90+75+45) - 140 = 210 - 140 = 70

Thanks,
Anshuman.

[Leaderboard]

a is not 0.6 \times 150 though. 90 is the number of houses that have air-conditioning, but a is the number of houses that have only air-conditioning (which is not the same thing).