Questions

Ans.  Suppose the speed of boat in still water is x km/h and speed of stream is y km/h

Speedof boat in downstream = (x + y) km/h x+ y = 32 …(i) 

Speed of boat in upstream = (x – y) km/h

x – y = 28 …(ii)

Add. Eqs. (i) and (ii), we get 2x = 60

x = 30 km/h

Protists are eukaryotic organisms that cannot be classified as a plant, animal, or fungus. They are mostly unicellular, but some, like algae, are multicellular.

Kelp, or 'seaweed,' is a large multicellular protist that provides food, shelter, and oxygen for numerous underwater ecosystems.

The Sahara is the largest non-polar desert in the world. The Sahara is the largest hot desert and the third largest desert in the world after Antarctica and the Arctic.

The desert covers large sections of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Western Sahara, Sudan and Tunisia. It covers 9 million square kilometers (3,500,000 sq mi), amounting to 31% of Africa.

Its borders include the Mediterranean Sea to the north, the Atlantic Ocean to the west and the Red Sea to the east.

Mercury was the remedy of choice for syphilis in Protestant Europe. Until the early 20th century, the primary treatment for syphilis was mercury, in the form of calomel, ointments, steam baths, pills, and other concoctions.

Mercury was already being used in Western Europe to treat skin diseases.

Most organic compounds contain carbon and hydrogen.

Rio Olympics were held in  Rio de Janeiro, Brazil, from 5 August to 21 August 2016.

• Athletes : 11303
• Countries : 207
• Events : 306