Please I need help with my math work I don’t understand it

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?

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?

The product of sin 30 degrees and sin 60 degrees is same as the product of