ব্যাংক আলফালাহ

প্রশ্নঃ Nazir can wash his car 15 minutes while his son takes twice as long. If they work together how many minutes will the job take them?

বর্ণনাঃ

His son can wash the car in (15 × 2 = 30) minutes

Nazir can wash 1/15 part of the car in 1 minute

His son can wash 1/30 part of the can in 1 minute

Together they can wash (1/15+1/30=1/10) part of the car in 1 minute

So, together they can wash the whole car in 10 minutes.

প্রশ্নঃ A batsman in his 17th innings makes a score of 85 and thereby increases his average by 3, his average after the 17th innings is :

বর্ণনাঃ

Let the average of the first 16 innings be A.

Total of the 16 innings = 16A

New average = A+3

New total of 17 innings, 17(A+3) = 16A+85

or,  17A+51=16A+85

or,  17A-16A=85-51

or, A = 34

So, new average after 17th innings = A+3 = 34+3 = 37

প্রশ্নঃ Income of A is 25% less than B. How much percent B's income would be more than that of A?

বর্ণনাঃ

Let their income be A and B respectively.

Now,  A = B - 25% of B = B - B/4 = 3B/4

or,  B = 4A/3

Now,  B-A = 4A/3 - A = A/3 = A/3 × 100% = 33.33% of A

প্রশ্নঃ Two pipes A & B would fill a tank in 20 & 30 minutes respectively. Both pipes being open, find when A must be turned off so that tank may be just filled in 15 minutes.

বর্ণনাঃ

Let the time be T minutes after which pipe A need to turned off. Both of the pipes remain open together only for T minutes.

Pipe A fills 1/20 of the tank in 1 minute.

Pipe B fills 1/30 of the tank in 1 minute

Together in 1 minute they fill (1/20+1/30=1/12) of the tank.

Together in T minutes they fill = T/12 of the tank

In (15-T) minutes, pipe B alone can fill = (15-T)/30 of the tank

Now, T/12 + (15-T)/30 = 1

or,  {15T + 6(15-T)}/180 = 1

or, (15T + 90 - 6T) / 180 = 1

or,  9T = 180 - 90

or,  9T = 90

So, T = 10 minutes

প্রশ্নঃ What percentage of profit is made by selling an article at a certain price if by selling at two third of that price there would be a loss of 20%?

বর্ণনাঃ

Let the cost price and sell price be A and S respectively.

ATQ,   (A - 2S/3) /A = 20/100

or,  (A - 2S/3) / A = 1/5

or, (A - 2S/3) = A/5

or, 2S/3 = A - A/5

or, 2S/3 = 4A/5

or, S = 4A/5 × 3/2

or, S = 6A/5

Now, profit = (S - A) / A × 100%

 = (6A/5 - A) / A × 100%

= (A/5) / A × 100%

= 20%

প্রশ্নঃ Divide Rs. 5625 among A, B & C so that A may receive 1/2 as much as B & C and B 1/4 of what A and C together receive?

বর্ণনাঃ

Let they receive A, B & C Rs. respectively.

Now, A = (B + C) / 2

or,  2A = B + C ----------(i)

Again, B = (A + C) / 4

or, 4B = (A + C)

or, 4B = (B + C) / 2 + C

or, 4B = B/2 + C/2 + C

or, 4B - B/2 = 3C/2

or, 7B/2 = 3C/2

or, B = 3C/7-------(ii)

Now, 2A = 3C/7 + C  [from (i)]

or, 2A = 10C/7

or, A = 5C/7------(iii)

From (ii) and (iii), 

B : C = 3 : 7

C : A = 7 : 5

So,  A : B : C = 5 : 3 : 7

A will receive = 5 / (5 + 3 + 7) × 5625 = 1875 Rs.

B will receive = 3 / (5 + 3 + 7) × 5625 = 1125 Rs.

C will receive = 7 / (5 + 3 + 7) × 5625 = 2625 Rs.

প্রশ্নঃ Business partnera A, B and C agree to divide their total profit for the year in the ratios 4 : 7 : 8 respectively. If A's share of the profit is Rs. 16,000, what was the total profit of the business partners for the year?

বর্ণনাঃ

Let the total profit be P.

Now, A's share of profit, 4 / (4 + 7 + 8) × P = 16000

or, 4P/19 = 16000

or, P = 16000 × 19 / 4 = 76000 Rs.

প্রশ্নঃ If Rs. 450/- amount to Rs. 504/- in three years at simple interest, what will Rs. 650/- amount in 2 years & 6 months the interest rate being the same in both cases?

বর্ণনাঃ

Here, 2 year 6 months = 2.5 years

Principal with simple interest, A = P( 1 + n r)

Now, 504 = 450( 1 + 3 × r)

or,  1+3r = 504/450

or, 3r = 504/450 - 1

or, 3r = (504 - 450) / 450

or, 3r = 54 / 450

or, r = 54 / (450 × 3)

or, r = 1/25

Again,  A = 650( 1 + 2.5 × 1/25)

or, A = 650 × (25+2.5)/25

or, A = 650 × 27.5 / 25

So, A = 715 Rs.

প্রশ্নঃ A glass when full of milk, weighs one kilogram. When half full, it weighs 3/4 kilogram. What is the weight of the empty glass?

বর্ণনাঃ

Weight of 1/2 glass of milk = 1 - 3/4 = 1/4 kg

So, weight of full glass of milk = 2 × 1/4 = 1/2 kg

So, weight of the glass = 1 - 1/2 = 1/2 kg = 0.5 kg

প্রশ্নঃ In a right angled triangle the horizontal side measures 8 cm and the vertical side measures 12 cm. What is the area of the triangle?

বর্ণনাঃ

Area of triangle = 1/2 × base × height = 1/2 × 8 × 12 = 48 cm²

প্রশ্নঃ Complete the series 4, 9, 17, 35,------

বর্ণনাঃ

4 × 2 + 1 = 9

9 × 2 - 1 = 17

17 × 2 + 1 = 35

35 × 2 - 1 = 69

প্রশ্নঃ Complete the series 1, 9, 17, 25, 33------

বর্ণনাঃ

1 + 8 = 9

9 + 8 = 17

17 + 8 = 25

25 + 8 = 33

33 + 8 = 41

প্রশ্নঃ If 12 years are added to 2/3 age of Rani, she will be three years older than today. What is Rani's present age?

বর্ণনাঃ

Let the present age of Rani be R.

Now, 2R/3 + 12 = R + 3

or, R - 2R/3 = 12 - 3

or, R/3 = 9

or, R = 27 years

প্রশ্নঃ A man travels 100 miles at 20 miles per hour, 60 miles at 30 miles per hour and 80 miles at 10 miles per hour, what is his average rate for the three trips?

বর্ণনাঃ

Time travelled at 20 miles//hr = 100/20 = 5 hrs

Time travelled at 30 miles//hr = 60/30 = 2 hrs

Time travelled at 10 miles//hr = 80/10 = 8 hrs

Total time travelled = 5 + 2 + 8 = 15 hrs

Total travelled = 100 + 60 + 80 = 240 miles

Average rate = 240 / 15 = 16 miles per hour

প্রশ্নঃ What is the area of a circle with a radius of 7 meters?

বর্ণনাঃ

Area = π R² = 22/7 × 7² = 154 m²

প্রশ্নঃ How much would I have to pay for a book which cost Rs. 72 to produce, if the printing company sold it to a book seller at 20% profit and the bookseller sold it to me at a profit of 25%?

বর্ণনাঃ

Book seller's buying price = 72 + 20% of 72 = 72 + 14.4 = 86.4 Rs.

Book seller's selling price = 86.4 + 25% of 86.4 = 108 Rs.

প্রশ্নঃ A sum of 24 is divided into two parts so that seven times the first part added to five times the second part makes 146. The value of first part is?

বর্ণনাঃ

Let the value of first and second part be F and (24-F) respectively.

Now, 7F + 5(24-F) = 146

or, 7F + 120 - 5F = 146

or, 2F = 146 - 120

or, F = 26/2 = 13

প্রশ্নঃ A sum of Rs. 1500.00 was put in two companies, one paid 6% simple interest and the other 5%. The whole annual interest from the two companies was Rs.85.00. What is the sum invested in the first company?

বর্ণনাঃ

Let the investments be F and (1500-F) Rs. in the companies respectively.

Interest, I = P n r

Now, F × 1 × 6/100 + (1500-F) × 1 × 5/100 = 85

or, 6F + 7500 - 5F = 8500 [multiplying both sides by 100]

or, F = 8500 - 7500

or, F = 1000 Rs.

প্রশ্নঃ How many signals can be given by 5 flags of different colours using 3 flags at a time.

বর্ণনাঃ

Possible ways = ⁵P₃ = 5 × 4 × 3 = 60 [Ways of choosing 3 flags from 5 flags is ⁵C₃. But different signals can be given bay rearranging those 3 flags in 3! ways. So, total possible ways of giving signal = ⁵C₃× 3! = ⁵P₃]

প্রশ্নঃ -----is the second largest Muslim country in the world :

বর্ণনাঃ

Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia.

It is the world's fifth-most populous country with a population exceeding 212.2 million, and has the world's second-largest Muslim population. Pakistan is the 33rd-largest country by area, spanning 881,913 square kilometres (340,509 square miles). It has a 1,046-kilometre (650-mile) coastline along the Arabian Sea and Gulf of Oman in the south and is bordered by India to the east, Afghanistan to the west, Iran to the southwest, and China to the northeast.

It is separated narrowly from Tajikistan by Afghanistan's Wakhan Corridor in the northwest, and also shares a maritime border with Oman.

প্রশ্নঃ ----is known as the city of mosques.

বর্ণনাঃ

Dhaka (formerly Dacca in English) is the capital and largest city of Bangladesh. 

It has been called the City of Mosques and the Venice of the East, due to its Islamic architecture and a riverfront facing the Buriganga (Old Ganges).

প্রশ্নঃ Worlds tallest building is ---

বর্ণনাঃ

The Burj Khalifa  literally "Khalifa Tower" in English), known as the Burj Dubai prior to its inauguration in 2010, is a skyscraper in Dubai, United Arab Emirates.

With a total height of 829.8 m (2,722 ft, just over half a mile) and a roof height (excluding antenna, but including a 244 m spire  of 828 m (2,717 ft), the Burj Khalifa has been the tallest structure and building in the world since its topping out in 2009 (preceded by Taipei 101).

প্রশ্নঃ Banglalink TM is a subsidiary of ----

বর্ণনাঃ

Banglalink Digital Communications Ltd.

eviously Orascom Telecom Bangladesh Ltd.) is the third largest cellular service provider in Bangladesh. It is fully owned by Telecom Ventures Ltd.

. It is a wholly owned subsidiary of Telecom Ventures Ltd. of Malta which is owned by Global Telecom Holding.