3 x 5 to the power of 2

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?

You buy 4 items that cost 2.69 14.45 8.05 13.95 what is the estimated total round to the nearest dollar

Can someone me with this? i’m not sure what to put for my equations.