Two mechanics worked on a car. The first mechanic worked for 10 hours and the second mechanic worked for 5 hours. Together they charged a total of $825. What is the rate charged per hour by each mechanic if the sum of the two rates was $120 per hour?

Aculture started with 3000 bacteria. after 5 hours it grew to 3900 bacteria. predict how many bacteria will be present after 9 hours

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?

Organic apples are on special for $1.50 per pound. does total cost vary inversely or directly with the number of pounds purchased? find the cost of 3.4 pounds of apples. a. inversely: $5.10 b. directly; $5.10 c. inversely: $2.27 d. directly; $2.27