A climber is scaling a rock face. Two hours after starting his climb, he is at an altitude of 400 feet. After six hours, he is at an altitude of 700 feet. What is his average rate of change?

A balloon was 10 feet off the ground when it was the child who was holding it let it go. 5 seconds after that, the balloon was 20 feet off the ground. What was the balloon's rate of ascent?

Craig earns extra money working as a lifeguard. He earned $37 after working for 4 hours and $64.75 after working for 7 hours. What was Craig's wage?

A scuba diver is 30 feet below the surface 10 seconds after she entered the water, and 100 feet below the surface after 40 seconds. What is this scuba diver's rate of descent? Round to the nearest hundredth.

A rocket is one mile above the earth 30 seconds after launch and five miles above the earth 2.5 minutes after launch. What is the rocket's rate of change in miles per second?

A chef weighed 145 lbs in 1986 and weighed 190 lbs in 2007. What was this chef's rate of change in weight?

Michael started a savings account. 4 weeks after starting this account, he had $300 dollars in it, and after 9 weeks, he had $400. What was the rate of change of money in his savings account over this time?

After 30 baseball games, A-Rod had 25 hits. If after 100 games he had 80 hits, what is his average number of hits per game?

Frank worked from 8:00 AM until 5:00 PM and made $80. What was his hourly rate of pay?

We like to think of _____________ as "where you ended up, minus where you started."