Questions

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.

Swift is the fastest among all the birds in India

UNIA - Universal Negro Improvement Association.

It is primarily in the United States, organization founded by Marcus Garvey, dedicated to racial pride, economic self-sufficiency, and the formation of an independent black nation in Africa.

In word, the mailing list is known as the Data source.