K+12>20 if k=15 true or false

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?

Acylinder and its dimensions are shown. which equation can be used to find v, the volume of the cylinder in cubic centimeters?

The radius of the earth is two times the radius of the moon. what fraction of the volume of the earth is the volume of the moon?