What was john's age 4 years ago if he will be y years old in 5 years

Need on this geometry question. explain how you did it.

The function show two sisters' savings account and the rate at which they plan to deposit money

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?