PEA key

[Abhitesh]

Hi,
14 C is neither quasi-convex nor convex.
22 D is 0.696.
Rest seems fine. This paper was solved in some haste so got few wrong answers.

In 8, use a2 + b2 + c2 + 2ab + 2bc + 2ca = 1+ 2A = (a+b+c)^2 >= 0 => A>=-1/2.
In 19, cases would be (1) squares have four neighbours. (2) three neighbours and (3) two neighbours.
In 21, check that f(x1+x2) = f(x1)+f(x2) and it is homogeneous of degree 1.

Q5 is based on Chinese remainder theorem, exact solution is time consuming. Best way is to check individual options.

[Halflife]

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[Abhitesh]

1/18

[Halflife]

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[Abhitesh]

Divide the numerator by 2. There is double counting.

[Halflife]

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[shiva]

How to solve 28th & 22nd question??

what could be the approach to solve.

[Halflife]

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[Seecha]

https://math.stackexchange.com/questions/861368/combinatorial-probability-question

[Halflife]

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[eco'17]

how to solve 16th question.
I did it this way, {90/5+110(4)/5} =106
but I'm not getting the answer, please help!

[happy]

2nd Question

A box contains 90 good and 10 defective screws. If 10 screws are drawn without replacement, the probability that none of them is defective is


Question says 10 screws are drawn without replacement

by saying without replacement , it means screws are drawn one by one without replacement

So we Should use Permutation Not Combination

the value ofoption C and A  are equal still i go for Option C

[Diya]

In Q. 21, with the following equations
f(x, y) = (x + 2y, x −y, −2x + 3y) and g(x, y) = (x + 1, y + 2), why aren't both linear transformations? Any addition, subtraction, multiplication or division can be considered as a linear operator, or am I missing something here?

[Diya]

22 is A

[Algaeconomics]

Hey halflife!
The answer for question 2 of PEA sample paper is A?
C gives the same answer na?
90C10/ 100C10 =90P10/ 100P10 ???

[Halflife]

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[Ravit]

simply use hypergeometric distribution

[Algaeconomics]

Haan yaar. I think combination hi hoga. because order is not important