Q:

Consider a regular hexagon ABCDEF. Two towers are situated at B and C. The angle of elevation from A to the top of the tower at B is 30 deg, and the angle of elevation to the top of the tower at C is 45 deg. What is the ratio of the height of towers at B and C?

A) 1:√3 B) 1:3
C) 1:2 D) 1:2√3
 
Answer & Explanation Answer: B) 1:3

Explanation:

Let the side of regular hexagon be ‘a’

Let height of the tower 1 be h1 and tower 2 be h2

Height of tower 1 = h1 = (distance between A and B)* (tan 30o)= a.1/√3

Distance between A and C = 2*√3.a/2= √3a

Height of tower 2 = h2 = (distance between A and C)* (tan 45o) = √3a.1 = √3a

Ratio of height of towers at B and C respectively =a/√3/√3a = 1/3.

 

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3 2601
Q:

Suppose 0 < θ < 90, then for every θ 4 sin2 θ + 1 is greater than or equal to ?

 

A) 2 B) 4 sin θ 
C) 4 cos θ  D) 4 tan θ
 
Answer & Explanation Answer: B) 4 sin θ 

Explanation:
We know that,
Arithmetic mean ≥ Geometric mean
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5 14034
Q:

What is the value of sin 46 cos 44+ cos 46 sin 44?

A) 2 B) sin 2
C) 1 D) 0
 
Answer & Explanation Answer: C) 1

Explanation:

sin 46. cos 44+ cos 46. sin 44

sin 46. sin (90 -44)+ cos 46. cos (90 -44)

= sin^2 46 + cos^2 46

= 1

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3 2411
Q:

If tan x = 1, 0 < x < 90, then what is the value of 2 sin x cos x?

A) 1/2 B) 1
C) √3/2 D) √3
 
Answer & Explanation Answer: B) 1

Explanation:

tan x = 1

then x = 45

2sin x. cos x = 2× 1/√2 x 1/√2 = 1

an x = 1
then
x = 45
o
2sin x. cos x =
2
×
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1 916
Q:

The expression 52n –23n has a factor?

A) 3 B)  7
C) 17 D) None of the above
 
Answer & Explanation Answer: C) 17

Explanation:
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3 1330
Q:

For the inequation x^2–7x + 12 > 0, which one of the following is correct ?

A) 3 < x < 4 B) –∞ < x < 3 only
C) 4 < x < ∞ only D) –∞ < x < 3 or 4 < x < ∞
 
Answer & Explanation Answer: D) –∞ < x < 3 or 4 < x < ∞

Explanation:
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1 965
Q:

If p and q are the roots of the equation x2 –15x + r = 0 and p –q = 1, then what is the value of r ?

A) 55 B) 56
C) 60 D) 64
 
Answer & Explanation Answer: B) 56

Explanation:

In the below equation,

x2–15x + r = 0

sum of roots = p + q = -(-15)/1 = 15 (sum of roots for equation ax2+ bx + c is -b/a)

product of roots = pq = r/1 = r     (product of roots for equation ax2+ bx + c is c/a)

given p –q = 1

also we know that p+q = 15

subtracting the squares of both

(p+q)2 + (p-q)2 = 15^2–1

p2 + q2 + 2pq –p2 –q2 +2pq = 225 -1

4pq = 224

4r = 224

r = 56

 

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0 1451
Q:

If ax= by= cz and b2= ac, then what is 1x+1z equal to ?

A) 1/y B) -1/y
C) 2/y D) -2/y
 
Answer & Explanation Answer: C) 2/y

Explanation:
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0 1436