The expression below represents the number of bacteria in a petri dish after t hours.

How to do this , and can some one explain

In the triangles, bc =de and ac fe.if the mzc is greater than the mze, then ab isdfelth

Aparticular telephone number is used to receive both voice calls and fax messages. suppose that 25% of the incoming calls involve fax messages, and consider a sample of 25 incoming calls. (a) what is the expected number of calls among the 25 that involve a fax message?