1
Q:

For any two real numbers a and b.

a-b2+b-a2 is

A) always zero B) never zero
C) positive only if a ≠ b D) positive if an only if a > b

Answer:   C) positive only if a ≠ b



Explanation:
Q:

n is an integer chosen at random from the set

{5, 7, 9, 11 }

p is chosen at random from the set

{2, 6, 10, 14, 18}

What is the probability that n + p = 23 ?

A) 0.1 B) 0.2
C) 0.25 D) 0.3
 
Answer & Explanation Answer: A) 0.1

Explanation:

Each of the integers in the first set could be combined with any from the second set, giving a total of 4 x 5 = 20 possible pairs.

Of these the combinations that could give a sum of 23 are (5 + 18), and (9 + 14)

This means that the probability of getting a sum of 23 is 2/20 = 1/10

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0 32468
Q:

A research team of 6 people is to be formed from 10 chemists,5 politicians, 8 economists and 15 biologists.How many teams have atleast 5 chemists?

A) 7350 B) 6400
C) 6379 D) 7266
 
Answer & Explanation Answer: D) 7266

Explanation:

10C5 x 28C1 x 10C6 = 7266

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0 3663
Q:

If there are 17 randomly placed dots on a circle,how many lines can you form using any 2 dots?

A) 126 B) 130
C) 136 D) 120
 
Answer & Explanation Answer: C) 136

Explanation:

17C2 = 136 (combination)

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0 3700
Q:

Course materials are sent to students by a distance teaching institution. The probability that they will send a wrong programme’s study material is 1/5. There is a probability of 3/4 that the package is damaged in transit, and there is a probability of 1/3 that there is a short shipment. What is the probability that the complete material for the course arrives without any damage in transit? 

A) 4/5 B) 2/3
C) 1/2 D) 2/15
 
Answer & Explanation Answer: D) 2/15

Explanation:

Probability of sending the correct material is 4/5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Probability of the material not being damaged in transit is 1/4

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Probability that there is no short shipment = 2/3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

∴ Required probability =4/5 x 1/4 x 2/3 = 2/15

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2 6517
Q:

Two cubes have their volumes in the ratio 1 : 27. Find the ratio of their surface areas.

A) 2:9 B) 3:9
C) 1:9 D) 4:9
 
Answer & Explanation Answer: C) 1:9

Explanation:

Let their edges be a and b. Then,

 

a3/b3 = 1/27 (or) (a/b)3 = (1/3)3 (or) (a/b) = (1/3).

 

\Ratio of their surface area = 6a2/6b2 = a2/b2 = (a/b)2 = 1/9, i.e. 1:9.

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31 14234
Q:

A cube of edge 15 cm is immersed completely in a rectangular vessel containing water . If the dimensions of the base of vessel are 20 cm x 15 cm, find the rise in water level

 

A) 11.25cm B) 11.56cm
C) 11.66cm D) 10.86cm
 
Answer & Explanation Answer: A) 11.25cm

Explanation:

Increase in volume = Volume of the cube = (15 x 15 x 15) cm3.

 

\Rise in water level = volume/area = (15 x 15 x 15)/(20 x 15) cm = 11.25 cm.

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7 13551
Q:

A bag contains 12 white and 18 black balls. Two balls are drawn in succession without replacement. What is the probability that first is white and second is black?

A) 6/145 B) 36/145
C) 18/95 D) 12/145
 
Answer & Explanation Answer: B) 36/145

Explanation:
 

The probability that first ball is white:
=C112C130=1230=25


Since, the ball is not replaced; hence the number of balls left in bag is 29.
Hence the probability the second ball is black:
=C118C129=1829


Required probability =(25)×(1829)


=36/145

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10 8274
Q:

Given a principal of $12,000 with a compound amount of $17,631.94 and interest rate of 8% compounded anually,what is the time peroid in years?

A) 3years B) 4years
C) 5years D) 6years
 
Answer & Explanation Answer: C) 5years

Explanation:

M=P(1+i)^n

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0 2810