Questions

India does not have any lake or sea comparable with the Great Lakes of the united States or the Caspian Sea of the CIS.

In a first, China is planning to send mini-ecosystems — containing potato seeds and silkworm eggs — to the Moon next year, in an attempt to study how the organisms develop on the lunar surface. The 3-kilogramme mini-ecosystem, developed by research teams led by Chongqing University in China, will be sent to the Moon by the Chang’e 4 scheduled to be launched in 2018, authorities announced at the Global Space Exploration Conference. An 18-centimetre-tall cylinder will carry potato seeds and silkworm eggs to be incubated.

The Whole car  - the body and inside - can be considered to be a hallow conductor. During the thunderstorm the body - i.e, the outside- gets a charge but there will be no charge inside. so the inside is safe.

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.