If you flip a coin 20 times and it lands on heads 7 times what is the theoretical probaility that it will land on heads

An advertising firm has an old computer that can prepare a whole mailing in 6 hours. with the of newer model the job is complete in 2 hours. how long would it take the newer model to do the job alone?

Asegment in the complex plane has a midpoint at 7 – 2i. if the segment has an endpoint at 11 – 3i, what is the other endpoint?

Can any one me with the answers to these questions asap?