The only active volcano in India is situated in Andaman-Nicobar islands.

Let that something be 'x'

From the given data,

x + x/5 = 21

5x + x/5 = 21

6x = 21 x 5

=> x = 17.5

Hence, that something is x = 17.5.

A search engines are a software systems used for searching about any information in the world on the web.

Search engines like Google, Bing, Internet explorer, Yahoo, etc... functions by providing relevant search results for the keywords user searches. 

Hence, the given statement is TRUE.

Hagia Sophia is the former Greek Orthodox Christian patriarchal cathedral, later an Ottoman imperial mosque and now a museum in Istanbul, Turkey.

It was built in 537 AD at the beginning of the Middle Ages, it was famous in particular for its massive dome. It was the world's largest building and an engineering marvel of its time.

The dome of the Hagia Sophia is supported by the four pendentives of the square corners.

Every year 5th September is celebrated as Teacher's Day in India, in the memory of Dr. Sarvepalli Radhakrishnan's birthday. He was the first vice-president and second president of India.

After he become the president of India, his students want to celebrate his birthday in grand but he refused and he adviced them to celebrate that day as teachers day. From then, 5th September is celebrated as Teacher's Day.

When heated any substance, the molecules move apart from each other. Alike in the air the molecules move apart from each other. We know that the warm air is lighter than the cool air. Since after heating air gets warmer, it floats up and the cool air comes down to occupy the warm air place.

Let the distance he covered each way = d kms

According to the question,

d/45 - d/50 = 1

=> d = 450 kms.

Hence, the total distance he covered in his way = d + d = 2 d = 2 x 450 = 900 kms.