A lawyer charges herclients $200 for the first hour of her time and $150 for each additionalhour. If the lawyer charged her newclient $1,550 for a certain number of hours of her time, how much was theaverage (arithmetic mean) charge per hour?

If ~$M=\sqrt{4}+\sqrt[3]{4}+\sqrt[4]{4}$~, then the value of M is

A certain library assessesfines for overdue books as follows. Onthe first day that a book is overdue, the total fine is $0.10. For each additional day that the book isoverdue, the total fine is either increased by $0.30 or doubled, whicheverresults in the lesser amount. What isthe total fine for a book on the fourth day it is overdue?

A long-distance telephonecompany charges a monthly fee of $4.95 plus $0.07 per minute for long-distancetelephone calls. If a person'slong-distance telephone calls for a certain month totaled 320 minutes, what wasthe total amount that the telephone company charged the person for that month?

Machine A, working alone atits constant rate, manufactures 280 bolts per hour, and machine B, working aloneat its constant rate, manufactures 220 bolts per hour. How many hours will it take for machines Aand B, working together at their respective constant rates, to manufacture1,000 bolts?

Each of 10 machines worksat the same constant rate doing a certain job. The amount of time needed by the 10 machines, working together, tocomplete the job is 16 hours. How manyhours would be needed if only 8 of the machines, working together, were used tocomplete the job?

In a survey of students,each student selected from a list of 12 songs the 2 songs that the studentliked best. If each song was selected 4times, how many students were surveyed?

The rate of a certainchemical reaction is directly proportional to the square of the concentrationof chemical A present and inversely proportional to the concentration ofchemical B present. If the concentrationof chemical B is increased by 100 percent, which of the following is closest tothe percent change in the concentration of chemical A required to keep thereaction rate unchanged?

If ~$\left (5 ^{21} \right )\left ( 4^{11} \right )=2\left ( 10^{n} \right )$~, what is the value of n ?

If x and y are integers and3^(x - 4) = 3^(y + 2), what is y in terms of x ?