Suppose A, B and C take x, x/2 and x/3 respectively to finish the work. 

Then, (1/x + 2/x + 3/x) = 1/2 

=> 6/x = 1/2      => x = 12 

So, B takes 6 hours to finish the work.

The capital of Bangladesh “Dhaka” is the world’s most crowded city with a population density of 44,500 people per square kilometre, released by World Economic Forum (WEF), citing UN Habitat data. According to UN Habitat data, of the top 10 most densely populated cities in the world, six are in Asia, three are in Africa and one is in South America. India’s financial capital Mumbai, home to 31,700 people per square kilometre has acquired second place, where as Kota in Rajasthan with 12,100 people per square kilometre was ranked seventh. Others in the list include Medellin in Columbia (3rd), Manila in Philippines (4th, 14,800), Casablanca in Morocco (5th, 14,200), Lagos in Nigeria (6th, 13,300), Singapore (8th, 10,200) and Jakarta in Indonesia (9th, 9,600).

SP2 = 2/3 SP1
CP = 100
SP2 = 80
2/3 SP1 = 80

SP1 = 120
100 --- 20   => 20%

The Kharoshi script is an ancient script used by the ancient Gandhara culture of South Asia primarily in modern-day Afghanistan and Pakistan to write the Gandhari language (a dialect of Prakrit) and the Sanskrit language.

Let the smallest number be x.
Then larger number = (x + 1365)
x + 1365 = 6x + 15
= 5x = 1350
x = 270
Smaller number = 270.

x = √8 - √7 = 1/(√8 + √7) and y = √6 - √5 = 1/(√6 + √5) and z = √10 - 3 = 1/(√10 + 3)

As (√8 + √7) > (√6 + √5), (√8 - √7) < (√6 - √5)

As (√10 + 3) > (√8 + √7) > (√6 + √5)

z < x < y.

The boring of India’s first underwater rail tunnel under the Hooghly River for establishing metro link between Howrah and Kolkata has completed before its scheduled deadline of July 2017. The tunnel is 16.6 km long, out of which 10.8 km runs under the ground. Of this 10.8 km, 502 metres is under the water and the whole thing connects Howrah to the west and Salt lake to the east. It will have 12 stations and six will be underground. Estimated cost of the entire project is $750 million or about Rs 5,000 crores. The final commissioning of the project is expected by December 2019, following which it will be operational. The project is built by Afcons Transtonnelstroy and implemented by Kolkata Metro Railway Corporation Ltd (KMRCL).

Total time taken = k/40 + 2k/20 hours

= 5k/40 = k/8 hours

Average speed = 3k/(k/8) = 24 kmph.