Which erosional force acts alone to produce avalanches and landslides?

8000 + 8800 + 8000 + 8 million + 80 trillion + another a katrillion equals

Can someone check if i did this correct. it’s number 4 if you’re wondering.

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?