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Q:

If a Siren sounds for every 5 seconds, how many times will it sound in ¾ of an hour?

A) 541 times	B) 540 times
C) 450 times	D) 275 times

Answer & Explanation Answer: A) 541 times

Explanation:

There are 60 minutes in an hour.

In ¾ of an hour there are (60 × ¾) minutes = 45 minutes.

In ¾ of an hour there are (60 × 45) seconds = 2700 seconds.

Siren sounds for every 5 seconds.

In 2700 seconds = 2700/5 = 540 times.

The count start after the first sound, the Siren will sound 541 times in ¾ of an hour.

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Filed Under: Clock puzzles
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Q:

Two goods trains each 520 m long, are running in opposite directions on parallel tracks. Their speeds are 42 km/hr and 36 km/hr respectively. Find the time taken by the slower train to cross the driver of the faster one ?

A) 60 sec	B) 48 sec
C) 45 sec	D) 34 sec

Answer & Explanation Answer: B) 48 sec

Explanation:

Relative speed = 42 + 36 = 78 km/hr = $\frac{65}{3}$ m/s

Distance = (520 + 520) =1040 mts.

Time = $1040 \times \frac{3}{65}$ = 48 sec

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Filed Under: Problems on Trains
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Q:

Two trains are running at 60 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 6 seconds. What is the length of the fast train ?

$A . 66 \frac{2}{3} m t s$

$B . 66 \frac{3}{2} m t s$

$C . 63 \frac{4}{5} m t s$

$D . 63 \frac{5}{4} m t s$

A) Option A	B) Option B
C) Option C	D) Option D

Answer & Explanation Answer: A) Option A

Explanation:

As Trains are moving in same direction,

Relative Speed = 60-20 = 40 kmph

--> $40 \times \frac{5}{18} = \frac{100}{9}$ m/sec

Length of Train= Speed * Time

Length = $\frac{100}{9} \times 6$

$\Rightarrow \frac{200}{3} = 66 \frac{2}{3} m t s$

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Filed Under: Problems on Trains
Exam Prep: CAT , Bank Exams
Job Role: Bank PO , Bank Clerk

Q:

After working for 8 days, Arun finds that only $\frac{1}{3}$ rd of the work has been done. He employs Akhil who is 60% as efficient as Arun. How many days more would Akhil take to complete the work?

A) 24.5 days	B) 26.6 days
C) 25 days	D) 20 days

Answer & Explanation Answer: B) 26.6 days

Explanation:

Arun has completed $\frac{1}{3}$ rd of the work in 8 days

Then he can complete the total work in

$\frac{1}{3}$ ---- 8

1 ---- ?

= 24 days

But given Akhil is only 60% as efficient as Arun

Akhil = $\frac{1}{24} \times \frac{60}{100} = \frac{1}{40}$

Akhil can complete the total work in 40 days

Now, remaining 2/3rd of work can be completed in

1 ------ 40

$\frac{2}{3}$ ------ ?

= 26.66 days.

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Filed Under: Time and Work
Exam Prep: CAT , Bank Exams
Job Role: Bank PO , Bank Clerk

Q:

Karthik read $\frac{6}{13}$ th of a book in 1st week and $\frac{5}{9}$ th of the remaining book in 2nd week. If there were 100 pages unread after 2nd week, how many pages were there in the book ?

A) 404	B) 415
C) 418	D) 420

Answer & Explanation Answer: C) 418

Explanation:

Let the total book be 1

Then, in the 1st week $\frac{6}{13}$ th of book is read

i.e remaining pages = $1 - \frac{6}{13} = \frac{7}{13}$

in 2nd week he read $\frac{5}{9}$ th of it

i.e $\frac{5}{9} \times \frac{7}{13} = \frac{35}{117}$
Remaining pages after 2nd week = $\frac{7}{13} - \frac{35}{117} = \frac{28}{117}$

But given remaining pages after 2nd week = 100

$\frac{28 x}{117} = 100$

--> x = 418

The total pages in the book are 418

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Filed Under: Decimal Fractions
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Q:

In a bag, there are 8 red, 7 blue and 6 green flowers. One of the flower is picked up randomly. What is the probability that it is neither red nor green ?

$A) \frac{1}{3}$

$B) \frac{8}{21}$

$C) \frac{6}{21}$

$D) \frac{20}{21}$

A) Option A	B) Option B
C) Option C	D) Option D

Answer & Explanation Answer: A) Option A

Explanation:

Total number of flowers = (8+7+6) = 21.

Let E = event that the flower drawn is neither red nor green.

= event taht the flower drawn is blue.

--> n(E)= 7

--> P(E)= $\frac{7}{21}$ = $\frac{1}{3}$

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Filed Under: Permutations and Combinations
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Q:

Raghu can complete a work in 12days working 9 hours a day. Arun can complete the same work in 8 days working 11 hours a day. If both Raghu and Arun work together, working 12 hours a day, in how many days can they complete the work ?

A) $3 \frac{4}{49} d a y s$

B) $12 \frac{4}{49} d a y s$

C) $4 \frac{3}{49} d a y s$

D) $4 \frac{12}{49} d a y s$

A) Option A	B) Option B
C) Option C	D) Option D

Answer & Explanation Answer: C) Option C

Explanation:

Raghu can complete the work in (12 x 9)hrs = 108 hrs.

Arun can complete the work in (8 x 11)hrs = 88 hrs.

Raghu's 1 hrs work = 1/108 and Arun's 1 hrs work = 1/88

(Raghu + Arun)'s 1 hrs work = $(\frac{1}{108} + \frac{1}{88}) = \frac{49}{2376}$

So, both Raghu and Arun will finish the work in $\frac{2376}{49} h r s$

Number of days of 12 hours each= $(\frac{2376}{49} \times \frac{1}{12})$ = $\frac{198}{49} = 4 \frac{3}{49} d a y s$

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Filed Under: Time and Work
Exam Prep: GATE , CAT , Bank Exams
Job Role: Bank PO , Bank Clerk

Q:

At what time, in minutes, between 3 o'clock and 4 o'clock, both the needles will coincide each other?

A. $5 \frac{1}{11}$

B. $15 \frac{4}{15}$

C. $16 \frac{4}{11}$

D. $4 \frac{4}{15}$

A) Option A	B) Option B
C) Option C	D) Option D

Answer & Explanation Answer: C) Option C

Explanation:

At 3 o'clock, the minute hand is 15 min. spaces apart from the hour hand.

To be coincident, it must gain 15 min. spaces.

55 min. are gained in 60 min.

Then 15 min spaces are gained in = $\frac{60}{55} \times 15$ min.

Therefore, The hands are coincident at $16 \frac{4}{11}$ min. past 3 o'clock.

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Filed Under: Clocks
Exam Prep: Bank Exams
Job Role: Bank Clerk

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