True or false an exponential decay function represents a quantity that has a constant doubling time

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?

What percent of 18 is 24? and plz explain thx.

Write a similarity statement for the similar triangles. afgh ~ a