Some cat biscuits are shared between Mittens and Bittens in the ratio 21:4 . What percentage of the biscuits did Mittens receive?

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?