The volume of a cylinder is 4x cubic units and its height is x units. Which expression represents the radius of the cylinder in units?
2x
4x
2πx^2
4πx^2

At a lunchron, guests are offered a selection of five different grilled vegetables and four different meats. in how many waya could one choose three vegetables and two meats?

Planning for the possibility that your home might get struck by lighting and catch on fire is part of a plan for ?

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?