You need 40% alcohol solutions. On hand, you have a 80 mL of a 20% alcohol mixture. You also have 50% alcohol mixture. How much of the 50% mixture will you need to add to obtain the desired solution?

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?