You are formatting a single hard disk for a Linux install. What is the maximum number of primary partitions you can create?

Answer: four

Explanation:
Generally in one System we can connect four Physical Harddisks. Asa Primary Master, Primary Slave, Secondary Master, Secondary Slave.

In One System: Either four Primary partitions or 1 Primary or 2 Primary or 3 Primary + 1 extended and all logical partitions will be create under extended partations.
Hardisk device recognized as follows Primary Master: /dev/hda Primary Slave: /dev/hdb Secondary Master: /dev/hdc Secondary Slave: /dev/hdd Suppose you have only single harddisk and going to install Linux, Maximum you can create 4 primary partitions. If you create four primary partitions you can’t create extended partitions that mean no logical partitions can create.