Which mineral is also known as 'fool's

According to the Quantity Theory of Money (QTM), what is the effect of a change in the velocity of money on the price level in the long run?

If a tax on a good is doubled, the deadweight loss from the tax

If Mean is 39, Median is 40, what is the value of Mode?

Which of the following statements correctly explains the convex shape of a typical indifference curve?

Any straight-line supply curve that has a positive horizontal intercept has an elasticity of supply