Questions

A Sandal.

It has sticking strips to make them fit for our feet. If you bind them only you can start walking or other wise it comes out.

Swift is the fastest among all the birds in India

Overhead costs should be figured into the cost estimate. Desired profit considered together with other factors such as market demand, availability of resources, prior experience are then used to determine the optimal price.

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.