Aschool replaced 20% of it computers with new ones . what the total number of computers in the school if 55 computers were replaced?

The marriott family bought a new apartment three years ago for $65,000. the apartment is now worth $86,515. assuming a steady rate of growth, what was the yearly rate of appreciation? what is the percent of the yearly rate of appreciation?

Carlos spent 1 1/4 hours doing his math homework he spent 1/4 of his time practicing his multiplication facts how many hours to carlos been practicing his multiplication facts

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).