Public Cloud: Computing services offered by third party provider over the public internet making them available to everyone who wants to use them services and infrastructure to various clients over a network which is open for public usage.
Better suited for business requirements which require managing the load, due to the decreased capital overheads and operational cost this model is economical.
Example: Microsoft Azure, Amazon Web Services etc.
Private Cloud: will provide computing power as a service within a Virtualized environment using an underlying pool of physical computing resources. However, under the private computing model, the cloud us only accessible by a single Organization, therefore providing that organization with greater control and privacy.
Hybrid: A type of Cloud Computing which is integrated, it can be an arrangement of two or more cloud servers, (Private, Public and Community that is bound together but remain individual entities. In a hybrid cloud, the resources are managed and provided either in-house or by external providers. It is an adaptation among two platforms in which the workload exchanges between the private cloud and the public cloud as per the need and demand.