811 . A circular wheel 28 inches in diameter rotates (moves) the same number of inches per second as a circular wheel 35 inches in diameter. If the smaller wheel makes x revolutions per second, how many revolutions per minute does the larger wheel make in terms of x?

A. 12x
B. 48x
C. 24x
D. 36x
E. None of these

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Answer: Option B

Explanation:

Let the revolutions made by larger wheel per minute be R.

Circumference of smaller wheel, 2 π r = 2 x π x (28/2) = 28π

Circumference of larger wheel, 2 π r = 2 x π x (35/2) = 35π

Speed of smaller wheel per minute = 60x

Distance covered by larger wheel per minute = Distance covered by smaller wheel per minute

or, R x 35π = 28π x 60x

or, R = 28π x 60x / 35π = 48x

প্রিমিয়াম প্ল্যান: ১ মাস

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সাবস্ক্রিপশন লিংক

812 . A circular wheel 28 inches in diameter rotates the same number of inches per second as a circular wheel 35 inches in diameter. If the smaller wheel makes x revolutions per second, how many revolutions per minutes does the larger wheel make in terms of x?

A. 12x
B. 24x
C. 36x
D. 48x

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Answer: Option D

Explanation:

ছোট চাকার ব্যাস = 28 ইঞ্চি

ছোট চাকার ব্যাসার্ধ r1 = 28/2 = 24 ইঞ্চি

ছোট চাকার পরিধি = 2πr1 = 28π ইঞ্চি

বড় চাকার ব্যাস = 35 ইঞ্চি

বড় চাকার ব্যাসার্ধ r2 = 35/2 ইঞ্চি

বড় চাকার পরিধি = 2πr2 = 2 × π × 35/2 = 35π ইঞ্চি

ছোট চাকাটি x বার ঘুরে যায় = 28πx ইঞ্চি

ছোট চাকাটি 1 সেকেন্ডে যায় = 28 πx ইঞ্চি

ছোট চাকাটি 60 সেকেন্ডে যায় = ( 60 × 28πx) = 1680πx ইঞ্চি

বড় চাকাটি 1 মিনিটে ঘুরবে = 1680πx /35π = 48x বার।

813 . A cistern can be filled in 10 hours but it takes 12 hours due to a leak in its bottom. If the cistern is full, then the time that the leak will take to empty it is:

A. 60 min
B. 80 h
C. 90 h
D. 60 h

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Answer: Option D

Explanation:

814 . A cistern is normally filled with eater in 10 hours but takes 5 hours longer to fill because of a leak in its bottom . If the cistern is full, the leak will empty the cistern in -

A. 20 hours
B. 30 hours
C. 40 hours
D. 50 hours

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Answer: Option B

Explanation:

জনতা ও রূপালী ব্যাংক- অফিসার ১৩.১২.২০১৯

A. 2/5
B. 3/5
C. 4/5
D. 3/2

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Answer: Option A

Explanation:

816 . A class of 120 has 25% girls. If 10% of the boys and 20% of the girls attended a picnic then what percentage of the class attended the picnic?

A. 20%
B. 25%
C. 13%
D. 12.5%
E. None of these

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Answer: Option D

Explanation:

Total students = 120

number of girls = 120*25% = 30

number of boys = (120 - 30) = 90

munber of students attended picnic = 90*10% + 30*20% = 6 + 4 = 15

% of students attended picnic = 15/120*100 = 12.5

ans: 12.5%

817 . A class of 50 girls and 70 boys sponsored a party. If 40% of the girls and 50% of the boys attended the party, approximately what percent of the class attended?

A. 40
B. 42
C. 44
D. 46

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Answer: Option D

Explanation:

First, we need to find out 40% of the 50 girls. That is 50 x 0.4 = 20 girls.

Next, we need to find out 50% of the 70 boys. That is 70 x 0.5 = 35 boys.

Therefore, 20 + 35 = 55 people attended.

In total there were 50 + 70 = 120 people.

So the percent would be 55/120 = 11/24 ≈ 45.83% ≈ 46%.

818 . A class of 80 students has 25% girls. If 10% of the boys and 20% of the girls attended a picnic then what percentage of the class attended the picnic ?

A. 20%
B. 25%
C. 13%
D. 12.5%
E. None of these

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Answer: Option D

Explanation:

25% of 80=20

So,

Girls=20

Boys=80-20=60

10% of 60=6

20% of 20=4

Total students=80, Students in picnic=6+4=10

Now,

(10×100)/80=12.5%

819 . A clock falls behind 10 minutes each day. How many days will it take to reach a point where the clock will indicate the correct time?

A. 36
B. 40
C. 72
D. 90

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Answer: Option C

Explanation:

Loss time for every day 10 min

Loss time for 6 days is 6×10 min = 60 min = 1 hours

i.e For every 6 days hour hand clock back 1 h

We know there are 12h in a clock

If the chock 12 backed then it will give us real time

So required time for showing real time is = 6×12 = 72 days

Ans. 72 days

820 . A clock is started at noon. By 10 minutes past 5, the hour hand has turned through :

A. 145 degree
B. 150 degree
C. 155 degree
D. 160 degree

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Answer: Option C

Explanation:

Hints: Angle traced by hour hand is 12 hrs = 360degree

Angle traced by hour hand in 5 hrs 10 min i.e, 31/6 hrs

= 360/12 × 31/6

= 155 degree

821 . A clock loses ( falls behind ) 10 minutes each day. How many days will take to reach a point where the clock will indicate the correct time ?

A. 36
B. 72
C. 120
D. None of these

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Answer: Option B

Explanation:

Loss time for every day 10 min

Loss time for 6 days is 6×10 min = 60 min = 1 hours

i.e For every 6 days hour hand clock back 1 h

We know there are 12h in a clock

If the chock 12 backed then it will give us real time

So required time for showing real time is = 6×12 = 72 days

Ans. 72 days

Bangladesh Bank - Officer - 2001

A. 3:15
B. 7:15
C. 8:45
D. 9:45

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Answer: Option C

Explanation:

Here, mirror ttime is = 3:15

So, Real time = 11:60-3:15 .(where 11-3 & 60-15)= 8:45

সমন্বিত ৭ ব্যাংক || অফিসার (ক্যাশ) (24-05-2024)

A. 3:15
B. 7:15
C. 8:45
D. 9:45

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Answer: Option C

Explanation:

Here, mirror ttime is = 3:15

So, Real time = 11:60-3:15 .(where 11-3 & 60-15)= 8:45.

সমন্বিত ৮ ব্যাংক ও ১ টি আর্থিক প্রতিষ্ঠান || সিনিয়র অফিসার (সাধারণ) (20-01-2023)

A. 3:15
B. 7:15
C. 8:45
D. 9:45

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Answer: Option C

Explanation:

Here, mirror time is = 3:15

So, Real time = 11:60-3:15 .(where 11-3 & 60-15)= 8:45.

সমন্বিত ৮ ব্যাংক ও ১ টি আর্থিক প্রতিষ্ঠান || অফিসার জেনারেল (10-03-2023)

A. 24 days
B. 30 days
C. 60 days
D. 60 hours

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Answer: Option C

Explanation:

1 hour = 60 min

24 hour = 1 day

Clock slows down by 1 min in 1 day

So, clock slows down by 60 min in 60 days.

811 . A circular wheel 28 inches in diameter rotates (moves) the same number of inches per second as a circular wheel 35 inches in diameter. If the smaller wheel makes x revolutions per second, how many revolutions per minute does the larger wheel make in terms of x?

812 . A circular wheel 28 inches in diameter rotates the same number of inches per second as a circular wheel 35 inches in diameter. If the smaller wheel makes x revolutions per second, how many revolutions per minutes does the larger wheel make in terms of x?

813 . A cistern can be filled in 10 hours but it takes 12 hours due to a leak in its bottom. If the cistern is full, then the time that the leak will take to empty it is:

814 . A cistern is normally filled with eater in 10 hours but takes 5 hours longer to fill because of a leak in its bottom . If the cistern is full, the leak will empty the cistern in -

815 . A class has 12 boys and 18 girls. What fraction of the class are boys?

816 . A class of 120 has 25% girls. If 10% of the boys and 20% of the girls attended a picnic then what percentage of the class attended the picnic?

817 . A class of 50 girls and 70 boys sponsored a party. If 40% of the girls and 50% of the boys attended the party, approximately what percent of the class attended?

818 . A class of 80 students has 25% girls. If 10% of the boys and 20% of the girls attended a picnic then what percentage of the class attended the picnic ?

819 . A clock falls behind 10 minutes each day. How many days will it take to reach a point where the clock will indicate the correct time?

820 . A clock is started at noon. By 10 minutes past 5, the hour hand has turned through :

821 . A clock loses ( falls behind ) 10 minutes each day. How many days will take to reach a point where the clock will indicate the correct time ?

822 . A clock seen through a mirror, shows quarter past three. What is the correct time shown by the clock?

823 . A clock seen through a mirror, shows quarter past three. What is the correct time shown by the clock?

824 . A clock seen through a mirror, shows quarter past three. What is the correct time shown by the clock?

825 . A clock slows down one minute every 24 hours. How long will it take to slow down by one hour?

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