Calcula:

a) 25% de 640=
b) 75% de 5.000=
c) 10% de 300=​

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 are the constants in this expression? -10.6+9/10+2/5m-2.4n+3m

The ratio of men to women working for a company is 4 to 5 . if there are 90 women working for the company, what is the total number of employees?