706 . A bag contains 2 red, 3 green and 2 blue balls .Two balls are drawn at random. What is the probability that none of the balls drawn is blue?

A. 5/7
B. 2/7
C. 10/21
D. 11/21

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Answer: Option C

Explanation:

Total number of balls
= (2 + 3 + 2)
= 7
Let S be the sample space
Then, n(S) = Number of ways of drawing 2 balls out of 7
n(S) = 7C2
n(S) = (7 × 6)/(2 × 1)
n(S) = 21
Let E = Event of 2 balls, none of which is blue
∴ n(E) = Number of ways of drawing 2 balls out of (2 + 3) balls
n(E) = 5C2
n(E) = (5 × 4)/(2 × 1)
n(E) = 10
∴P(E) = n(E)/n(S) = 10/21

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সমন্বিত ৬ (ব্যাংক) ও ২ টি আর্থিক প্রতিষ্ঠান - সিনিয়র অফিসার ১০.০৬.২০১৯

A. 3
B. 6
C. 8
D. 10
E. None of them

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Answer: Option D

Explanation:

To be sure that Jason has at least one marble of each color (red, white, and blue), he should continue removing marbles until he has exhausted all of one color. In this case, we want to find the least number of marbles he must remove to ensure he has at least one marble of each color.

The maximum number of marbles of a single color (blue, in this case) is 5. So, Jason must remove all the white and red marbles first before he can be sure he has at least one marble of each color.

Number of white and red marbles = 4 white + 3 red = 7

Now, Jason must remove all 7 of these marbles before he can be sure he has at least one marble of each color.

Therefore, the least number of marbles he must remove is 7 (to remove all the white and red marbles) + 3 (to remove the remaining red marbles) = 10.

So, the least number of marbles he must remove to ensure he has at least one of each color is 10.

The correct answer is 10.

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708 . A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at rand dom from the bag. The probability that all of them are red.is:

A. $\frac{1}{22}$
B. $\frac{2}{91}$
C. $\frac{3}{22}$
D. $\frac{2}{77}$

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Answer: Option B

Explanation:

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অফিসার (ক্যাশ ) - Sonali | Rupali | BD Krishi | Rajshahi Krishi Unnayn | Investment Corporation Of Bangladesh - ২৯. ০৩.২০১৯

A. 1/14
B. 2/7
C. 5/7
D. 3/14

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Answer: Option B

Explanation:

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Uttara Bank PLC || Probationary Officer (09-11-2024) || 2024

A. 81
B. 36
C. 72
D. 40

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Answer: Option A

Explanation:

18 chickens can feed for = 54 days

1 chicken can feed for = (54*18) days

12 chickens can feed for = (54*18)/12 days

= 81 days

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711 . A ball pen factory decided to reduce its production by 10% over that of previous month for next 3 months starting from February 1994. In January 1994, it produced 3000 ball pens. How many ball pens were produced in March 1994?

A. 2187
B. 2400
C. 2700
D. 2430

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Answer: Option D

Explanation:

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712 . A bar of soap has a volume of 18 cubic inches. Jasim used it until it measured 2.75 inches by 2 inches by 1 inch. How many cubic inches of soap did jasim use?

A. 14.25
B. 5.75
C. 8.5
D. 12.5

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Answer: Option D

Explanation:

Jashim use=18-(2.75×2×1)=12.5

(ans)

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713 . A batsman makes a score of 80 runs in the 16th innings and increases average by 3. What is his average after 16th innings?

A. 25
B. 29
C. 32
D. 35

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Answer: Option D

Explanation:

Let,

Average of the 15 innings = x

So, the total runs of the 15 innings = x × 15

ATQ,

(x × 15 + 80)/16 = x + 3

=> 15x + 80 = 16x + 48

=> x = 80-48 = 32

So, the average of the 16th innings = 32+3 = 35

Ans. 35.

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NRBC Bank PLC || Trainee Assistant Officer (TAO) (26-10-2024) || 2024

A. 10/21
B. 11/21
C. 2/7
D. 5/7

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Answer: Option A

Explanation:

n(S) = 7C2 = 21

n( E) = 5C2 = 5! /2! 3! = 10

কোনো বলই নীল না হওয়ার সম্ভাবনা = n( E) / n(S) = 10/21

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715 . A bell rings every 15 minute. If the bell rang at 12.40, which of the following could be a time at which the bell had sounded?

A. 5:30
B. 6:45
C. 7:15
D. 8:10

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Answer: Option D

Explanation:

Very easy technique.

Every hour is 60 minutes, which is divisible by 15.

That means once the bell rang, every hour it will ring no matter what.

So it will ring at 1.40, 2.40, and so on.

It will ring at 5.40 (so it can't be 5:30 because 5.40-5.30= 10 minutes apart)

It will ring at 6.40 (so it can't be 6:45 because 6.45-6.40= 5 minutes apart)

It will ring at 7.40 (so it can't be 7:15 because 7.40-7.15= 25 minutes apart)

It will ring at 8.40 (so it will be 8:10 because 8.40-8.10= 30 minutes apart which is also divisible by 15).

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716 . A board of length L feet is cut into two pieces such that the length of one piece is 1 foot more than twice the length of the other piece. Which of the following is the length, in feet, of the longer piece?

A. (2L+1)/2
B. (L-1)/3
C. (2L+3)/3
D. (2L+1)/3

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Answer: Option D

Explanation:

Let length of piece A = 2x - 1

length of piece B = x

2x - 1 + x = L

= >3x - 1 = L

= >x = (L + 1)/3

length of piece A = 2[(L + 1)/3] - 1

= (2L + 2 - 3)/3 = (2L - 1)/3

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717 . A boat can travel form point A to point B and return back to point a in 9 hours. Speed of the boat in still water is 8 km/h and the speed of the stream is 4 km/h. Find the distance between A and B.

A. 18 km
B. 27 km
C. 36 km
D. 45 km

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Answer: Option B

Explanation:

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Officer (General) |-Sonali | Janata | Bangladesh Krishi_Bangladesh Development bank ২৪.০৫.২০১৯

A. 2 hours
B. 3 hours
C. 4 hours
D. 5 hours
E. None of these

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Answer: Option C

Explanation:

Downstream speed = speed of boat + speed of stream

= 13 km/hr + 4 km/hr

= 17 km/hr

Now, 17 km goes in 1 hour

1 km goes in 1/17 hour

68 km goes in ( 68×1)/17 hour = 4 hour

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অফিসার (ক্যাশ ) - Sonali | Rupali | BD Krishi | Rajshahi Krishi Unnayn | Investment Corporation Of Bangladesh - ২৯. ০৩.২০১৯

A. 10 km/hr
B. 12 km/hr
C. 14 km/hr
D. 8 km/hr

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Answer: Option B

Explanation:

Let the speed of the boat and speed of the stream be x km/hr and y km/hr respectively

According to the question,

143 / (x - y) = 13 - (- - - (i))

143 / (x + y) =11-***=(ii)

On comparing both eq

11(x + y) = 13(x - y)

11x + 11y = 13x - 13y

24y = 2x

x / y = 12/1
Ans: Speed of the boat in still water is 12 km/hr

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Janata Bank PLC || Officer (Rural Credit) (27-10-2023) || 2023

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

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Answer: Option B

Explanation:

boat speed + steam speed = 8 km/hour

boat speed - steam speed = 2 km/hour

(Doing Subtraction), 2*(steam speed) = 6 km/hour

steam speed = 6/2 = 3 km/hour (Ans)

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বিসিআইসি | সহকারী প্রকৌশলী (কমার্শিয়াল) | 10-12-2021 || 2021

706 . A bag contains 2 red, 3 green and 2 blue balls .Two balls are drawn at random. What is the probability that none of the balls drawn is blue?

707 . A bag contains 3 red, 4 white and 5 blue marbles. Jason begins removing marbles from the bag at random, one at a time. what is the least number of marbles he must remove to sure that he has at least one of each color?

709 . A bag contains 6 red balls, 11 yellow balls and 5 pink balls. If two balls are drawn at random from the bag one after another, what is the probability that the first ball is red and the second ball is yellow?

710 . A bag of chicken feed can feed 18 chickens for 54 days. For how many days will it feed 12 chickens?

711 . A ball pen factory decided to reduce its production by 10% over that of previous month for next 3 months starting from February 1994. In January 1994, it produced 3000 ball pens. How many ball pens were produced in March 1994?

712 . A bar of soap has a volume of 18 cubic inches. Jasim used it until it measured 2.75 inches by 2 inches by 1 inch. How many cubic inches of soap did jasim use?

713 . A batsman makes a score of 80 runs in the 16th innings and increases average by 3. What is his average after 16th innings?

714 . A beg contains 2 red, 3 green and 2 blue balls. If two balls are drawn at random, what is the probability that none of the balls drawn is blue ?

715 . A bell rings every 15 minute. If the bell rang at 12.40, which of the following could be a time at which the bell had sounded?

716 . A board of length L feet is cut into two pieces such that the length of one piece is 1 foot more than twice the length of the other piece. Which of the following is the length, in feet, of the longer piece?

717 . A boat can travel form point A to point B and return back to point a in 9 hours. Speed of the boat in still water is 8 km/h and the speed of the stream is 4 km/h. Find the distance between A and B.

718 . A boat can travel with a speed of 13 km/hr in still water. If the speed of the stream is 4 km/hr, find the time taken by the boat to go 68 km downstream.

719 . A boat covers 143 km upstream in 13 hours and the same distance downstream in 11 hours. What is the speed (in km / hr ) of the boat in still (without stream) water?

720 . A boat goes 8 km in one hour along the steam and 2 km in one hour against the stream, The speed in km/hr of the stream is.

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