55
Q:

If a + b + c = 13, a2+b2+c2=69 then find the ab + bc + ca :

A) 10 B) 30
C) 50 D) 70

Answer:   C) 50



Explanation:

a+b+c2=a2+b2+c2+2ab+bc+ca

2ab+bc+ca=a+b+c2-a2+b2+c2=169-69=100=ab+bc+ca=50

Q:

The radii of the two circular faces of the frustum of a cone of height 21 cm are 5 cm and 3 cm. What is its volume in cm^3(pi = frac{22}{7})

 

A) 1020 B) 1058
C) 1078 D) 1025
 
Answer & Explanation Answer: C) 1078

Explanation:
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0 8
Q:

If a + b + c = 6 and ab + bc + ca = 5, then a^3 + b^3 + c^3 - 3abc is equal to:

 

A) 108 B) 126
C) 98 D) 116
 
Answer & Explanation Answer: B) 126

Explanation:
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0 94
Q:

The value of: 3.8 + (8.2 div 4.1 times 2) - 4 times 3 div 1.2

 

A) 1.2 B) -2.2
C) 2.2 D) -1.2
 
Answer & Explanation Answer: B) -2.2

Explanation:
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0 19
Q:

The value of : 108 ÷ 36 × 4 + 2.5 × 4 ÷ 0.5 − 10

 

A) 20 B) 22
C) 16 D) 18
 
Answer & Explanation Answer: B) 22

Explanation:
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0 45
Q:

The value of -5/2 + 3/2 / 6 x 1/2 is equal to

 

A) -1/3 B) -1/12
C) -19/8 D) -9/8
 
Answer & Explanation Answer: C) -19/8

Explanation:
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0 140
Q:

In a circle of radius 17 cm, a chordis at a distance of 8 cm from the centre of the circle. What is the length of the chord?

 

A) 20 cm B) 15 cm
C) 25 cm D) 30 cm
 
Answer & Explanation Answer: D) 30 cm

Explanation:
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0 218
Q:

In ABC, P is a point on BC such that BP : PC = 4 : 11. If Q is the midpoint of BP, then ar( ABQ) : ar( ABC) is equal to:

 

A) 2:11 B) 2:15
C) 3:13 D) 2:13
 
Answer & Explanation Answer: B) 2:15

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0 181
Q:

The value of frac{tan^2 theta - sin^2 theta}{2 + tan^2 theta + cot^2 theta} is:

 

A) \cosec^6 \theta B) \cos^4 \theta
C) \sin^6 \theta D) \sec^4 \theta
 
Answer & Explanation Answer: C) \sin^6 \theta

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1 118