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Q:

The insects do not have blood pigments because

A) there is no blood	B) blood does not have a respirratory function
C) tissues have pigments	D) pigments are elsewhere

Answer & Explanation Answer: B) blood does not have a respirratory function

Explanation:

The blood of some invertebrate animals like the earthworm is red due to haemoglobin pigment, but the pigment is dissolved in the plasma. In vertebrates the same pigment is found in the red corpuscles and not in the plasma.

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Filed Under: Biology

Q:

In addition to nitric acid, another acid which may render iron passive is

A) acetic acid	B) oxalic acid
C) chromic acid	D) citric acid

Answer & Explanation Answer: C) chromic acid

Explanation:

Passivity of iron is due to formation of an extremely thin and impervious film of ferrosoferric oxide $[F e_{3} (O_{4})]$ on the surface of iron. Chromic acid, being a powerful oxidising agent (like nitric acid ) renders iron passive.

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Filed Under: Chemistry

Q:

When one enters a dark room after being in bright light one is not able to see anything clearly for a while because

A) the retina of the eye moves forward	B) the retina of the eye moves backward
C) the iris is unable to dilate the pupil immediately to be able to see things	D) the eye has no power of accommodation

Answer & Explanation Answer: C) the iris is unable to dilate the pupil immediately to be able to see things

Explanation:

The size of the pupil of the automatically adjusts itself according to the intensity of light passing through it; if the intensity is more, the size is less, if less, it is more. So in our case the pupil should dilate i.e , increase in size to be able to see in the dark. This switchover takes some time. But here the entry into the dark room is immediate. So the eye has no time to adjust itself and hence is not able to see at all for a while.

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Filed Under: Physics

Q:

There are three boats B1, B2 and B3 working together they carry 60 people in each trip. One day an early morning B1 carried 50 people in few trips alone. When it stopped carrying the passengers B2 and B3 started carrying the people together. It took a total of 10 trips to carry 300 people by B1, B2 and B3. It is known that each day on an average 300 people cross the river using only one of the 3 boats B1, B2 and B3. How many trips it would take to B1, to carry 150 passengers alone?

A) 15	B) 30
C) 25	D) 10

Answer & Explanation Answer: A) 15

Explanation:

Combined efficiency of all the three boats = 60 passenger/trip

Now, consider option(a)

15 trips and 150 passengers means efficiency of B1 = 10 passenger/trip

which means in carrying 50 passengers B1 must has taken 5 trips. So the rest trips equal to 5 (10-5 = 5) in which B2 and B3 together carried remaining 250 (300 - 50 = 250) Passengers.

Therefore the efficiency of B2 and B3 = 250/5 = 50 passenger/trip

Since, the combined efficiency of B1, B2 and B3 is 60. Which is same as given in the first statement hence option(a) is correct.

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Filed Under: Time and Work

Q:

A fast moving superfast express crosses another pasenger train in 20 seconds. The speed of faster train is 72 km/hr and speeds of slower train is 27 km/h. Also the length of faster ntrain is 100m, then find the length of the slower train if they are moving in the same direction.

A) 100 m	B) 125 m
C) 150 m	D) 175 m

Answer & Explanation Answer: C) 150 m

Explanation:

$T i m e = \frac{S u m o f l e n g t h o f t h e t w o t r a i n s}{D i f f e r e n c e i n s p e e d s}$

$20 = \frac{(100 + x)}{\frac{25}{2}}$

$\Rightarrow$ X=150m

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Filed Under: Logarithms

Q:

The distance of the college and home of Rajeev is 80km. One day he was late by 1 hour than the normal time to leave for the college, so he increased his speed by 4km/h and thus he reached to college at the normal time. What is the changed (or increased) speed of Rajeev?

A) 28 km/h	B) 30 km/h
C) 40 km/h	D) 20 km/h

Answer & Explanation Answer: D) 20 km/h

Explanation:

Let the normal speed be x km/h, then

$\frac{80}{x} - \frac{80}{(x + 4)} = 1$

$\Rightarrow$ $x^{2} + 4 x - 320 = 0$

$\Rightarrow$ x (x + 20) - 16 (x + 20) = 0

(x + 20 ) (x - 16) =0

x = 16 km/h

Therefore (x + 4) = 20 km/h

Therefore increased speed = 20 km/h

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Filed Under: Time and Distance

Q:

A letter is takenout at random from 'ASSISTANT' and another is taken out from 'STATISTICS'. The probability that they are the same letter is :

A) 35/96	B) 19/90
C) 19/96	D) None of these

Answer & Explanation Answer: B) 19/90

Explanation:

$A S S I S T A N T \to A A I N S S S T T$

$S T A T I S T I C S \to A C I I S S S T T T$

Here N and C are not common and same letters can be A, I, S, T. Therefore

Probability of choosing A = $\frac{2_{C_{1}}}{9_{C_{1}}} \times \frac{1_{C_{1}}}{10_{C_{1}}}$ = 1/45

Probability of choosing I = $\frac{1}{9_{C_{1}}} \times \frac{2_{C_{1}}}{10_{C_{1}}}$ = 1/45

Probability of choosing S = $\frac{3_{C_{1}}}{9_{C_{1}}} \times \frac{3_{C_{1}}}{10_{C_{1}}}$ = 1/10

Probability of choosing T = $\frac{2_{C_{1}}}{9_{C_{1}}} \times \frac{3_{C_{1}}}{10_{C_{1}}}$ = 1/15

Hence, Required probability = $\frac{1}{45} + \frac{1}{45} + \frac{1}{10} + \frac{1}{15} = \frac{19}{90}$

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Filed Under: Probability
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Q:

A coin is tossed twice if the coin shows head it is tossed again but if it shows a tail then a die is tossed. If 8 possible outcomes are equally likely. Find the probability that the die shows a number greater than 4, if it is known that the first throw of the coin results in a tail

A) 1/3	B) 2/3
C) 2/5	D) 4/15

Answer & Explanation Answer: A) 1/3

Explanation:

Here Sample space S = { HH, HT, T1, T2, T3, T4, T5, T6 }

Let A be the event that the die shows a number greater than 4 and B be the event that the first throw of the coin results in a tail then,

A = { T5, T6 }

B = { T1, T2, T3, T4, T5, T6 }

Therefore, Required probability = $P (\frac{A}{B}) = \frac{P (A \cap B)}{P (B)} = \frac{\frac{2}{8}}{\frac{6}{8}} = \frac{1}{3}$

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Filed Under: Probability

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