Does anyone know what math topic this is?

If 20% of a number is 35, what is 50% of that number?

What effect would doubling all the dimensions of a triangular pyramid have on the volume of the pyramid? explain your reasoning.

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. 4x^2 + 20x + 25 = 0