Questions

mercaptans (or thioalcohols) have a foul odour

Let the two digits be x & y

From given data in the question, we get

x + y = 3(x - y)

x + y = 3x - 3y

=> 2x = 4y

x/y = 2/1

For having the 2:1, numbers satisfying are

12, 21, 24, 42, 36, 63, 48, 84

From this 36 is eleminated because it is a perfect square and no others are prime or perfect squares.

Hence, there exists 7 such 2-digit numbers => 12, 21, 24, 42, 63, 48, 84.

The red blood corpuscles or Erythrocytes usually carry antigens and there are two types of antigens. The A group persons have antigen A in their red corpuscles and the B group have antigen A in their red corpuscles.The AB group persons have both antigen A and antigen B in their erythrocytes.The 'O'group persons have no antigens in their red corpuscles.

Duge Beipanjiang Bridge in southwest China, opened to traffic this week and now the highest bridge in the world, some 565 metres (1,854 feet) above the valley below.The bridge stretches across a 1,341-metre (4,400-foot) span. Three years in the making, it's estimated to have cost the Chinese government around 1 billion yuan (or US$144 million).The bridge is going to cut travel times between Liupanshui in the Guizhou province and Xuanwei in the Yunnan province to two hours instead of the current five – as long as you don't mind the heights.The bridge crosses the the Nizhu river, and to give you some idea of the size of the drop down to the water below, it's almost 2 Eiffel Towers or one-and-a-half Empire State Buildings.

Swift is the fastest among all the birds in India