Quant * Questions / Error Log

Question 1

Solve -

stats

Answer 1

1. To solve this first, think about are they consecutive? Yes!
2. Then, you know that this is in AP, so the sum of first and last term is (a + b), and the average = (a + b) / 2 = 3b/4.
3. Similarly, next equation will come from (b+c)/2 = 7c/8.
4. Now, (c+a)/2, you can easily solve by putting in values coming from two equations above.

Answer is 11c/16

If consecutive dia hai, toh AP ke baare mein ek do baar socho. You may hit the spot.

Question 2

Solve -

stats

Answer 2

Here, you marked D, thinking that x is less than 1, so it will be zero or -1 or something more.

But one thing you didn’t consider are decimals. The set can be - {0.9, 1, 2} (more compact, so less SD) or {-10000, 1, 2} (more spread, so more SD),
So, we can’t really say by (2).

Point - Consider decimals in places where integers are not mentioned khud se. Consider ek do decimals as well, something from -> 0-1, more than 1, and negative side bhi.

Question 3

Solve -

stats

Answer 3

Don’t go solving by doing random stuffs, be focued and follow a specific way of doing things.

a + b + c + d + e = 250 (a < b < c…)
Here, we want to maximize e, so rest of them should minimize.
c = 50
b = a (since we want lowest possible)
d = 50 (since lowest)

So, a + a + 50 + 50 + e = 250, where e = 3a+5 (given)
e = 92.

Question 4

Solve -

numbers

Answer 4

Here, the major blunder you did was - you took y^4 as 81. Which is correct but not entirely. You have to consider decimal values as well.

Since y^4 = odd, then Root(odd) = odd, so y^2 = odd.

Now, since given that positive integer divisible by y2, so y2 has to be an integer and odd.

y2 can be = 1 | 3 | 5 | 7 | 9 | 11 | 13…
but
y4 can only be 2 digit odd integers,
so y2 -> 5 | 7 | 9
so y4 -> 25 | 49 | 81
anything beyond is not two digits.

Last conclusion, n is divisible by 5 / 7 / 9. Now solve the question, you can easily do it.

No one told you that y is an integer. y2 has to be an integer (from your

Question 5

Solve -

numbers

Answer 5

7x is even.

7 * (2/7) = 2 (which is even) but x is not even.

Nowhere, it’s written that x is an integer.

7x = Even
5x = Even
- - - - - - - - - - (subtract)
2x = Even

x = Even / 2, so x is even.

mf, consider fractions.

Question 6

Solve -

numbers

Answer 6

Rather than taking the square root, square both the sides,
63 - 36{root(3)} = x^2 + 3y^2 + 2xy{root3}

so, -36{root(3)} = 2xy{root3}

xy = -18, easily.

Question 7

• Solve -

coordinate

Answer 7

Median bisects the line of a triangle. (Not perpendicular)
in the equation of the line, it’s just slope only, nothing new formula. lol

Question 8

• Solve -

coordinate

Answer 8

The midpoint is parallel to the side, that is the main catch here to find the slope. If you know that, you know that.