Math question pls help: A rectangular pyramid has a height of 8 cm and a base that is 6cm by 4cm. Find the volume

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?

Three times the sum of a number and seven is negative thirty-six. what is the number?

What is the value of m in the equation 1/2 m - 3/4n=16 when n=8