1
AP EAPCET 2025 - 27th May Morning Shift
MCQ (Single Correct Answer)
+1
-0

Let $X$ be the random variable taking values $1,2, \ldots n$ for a fixed positive integer $n$. If $P(X=k)=\frac{1}{n}$ for $1 \leq k \leq n$, then the variance of $X$ is

A

$\frac{n^2-1}{12}$

B

$\frac{n^2+1}{12}$

C

$\frac{n^2-1}{6}$

D

$\frac{(n+1)(n+2)}{6}$

2
AP EAPCET 2025 - 27th May Morning Shift
MCQ (Single Correct Answer)
+1
-0

A radar system can detect an enemy plane in one out of ten consecutive scans.

The probability that it can detect an enemy plane atleast twice in four consecutive scans is

A

0.0422

B

0.0523

C

0.0535

D

0.0623

3
AP EAPCET 2025 - 27th May Morning Shift
MCQ (Single Correct Answer)
+1
-0

The locus of the third vertex of a right-angled triangle, the ends of whose hypotenuse are $(1,2)$ and $(4,5)$ is

A

$x^2+y^2+5 x+7 y+14=0$

B

$3 x+3 y-1=0$

C

$3 x+3 y+1=0$

D

$x^2+y^2-5 x-7 y+14=0$

4
AP EAPCET 2025 - 27th May Morning Shift
MCQ (Single Correct Answer)
+1
-0

The coordinate axes are rotated about the origin in the counter clockwise direction through an angle $60^{\circ}$. If a and $b$ are the intercepts made on the new axes by a straight line whose equation referred to the original axes is $x+y=1$, then $\frac{1}{a^2}+\frac{1}{b^2}=$

A

2

B

3

C

4

D

6