Consider the data on x taking the values 0, 2, 4,
8,....., 2n with frequencies nC0
,
nC1
,
nC2
,....,
nCn
respectively. If the mean of this data is $${{728} \over {{2^n}}}$$, then n is equal to _________ .
Answer
6
11
If $$\overrightarrow x $$ and $$\overrightarrow y $$ be two non-zero vectors such that
$$\left| {\overrightarrow x + \overrightarrow y } \right| = \left| {\overrightarrow x } \right|$$ and $${2\overrightarrow x + \lambda \overrightarrow y }$$ is perpendicular to $${\overrightarrow y }$$,
then the value of $$\lambda $$ is _________ .
Answer
1
12
Suppose that a function f : R $$ \to $$ R satisfies
f(x + y) = f(x)f(y) for all x, y $$ \in $$ R and f(1) = 3. If $$\sum\limits_{i = 1}^n {f(i)} = 363$$ then n is equal to ________ .
Answer
5
13
The number of words (with or without meaning)
that can be formed from all the letters of the
word “LETTER” in which vowels never come
together is ________ .
Answer
120
14
The common difference of the A.P. b1, b2, … , bm
is 2 more than the common difference of A.P. a1, a2, …, an. If a40 = –159, a100 = –399 and
b100 = a70, then b1
is equal to :
Answer
(D)
-81
15
The probabilities of three events A, B and C are
given by P(A) = 0.6, P(B) = 0.4 and P(C) = 0.5.
If P(A$$ \cup $$B) = 0.8, P(A$$ \cap $$C) = 0.3, P(A$$ \cap $$B$$ \cap $$C) = 0.2,
P(B$$ \cap $$C) = $$\beta $$ and P(A$$ \cup $$B$$ \cup $$C) = $$\alpha $$, where
0.85 $$ \le \alpha \le $$ 0.95, then $$\beta $$ lies in the interval :
Answer
(C)
[0.25, 0.35]
16
If $$\alpha $$ and $$\beta $$ are the roots of the equation
2x(2x + 1) = 1, then $$\beta $$ is equal to :