Textbook page 61, number 15 A

15) In dry air, the temperature decreases by about 0.65 degrees Celsius for each 100-m increase in altitude.

A)The temperature in Red Deer, Alberta, is 10 degrees Celsius in a dry air. What is the temperature outside an aircraft 2.8 km above the city?

0.65x28= 18.2

18.2-10= -8.2

The temperature outside an aircraft is -8.2 degrees Celsius.