If the temperature decreases by 2 degrees per 1000 feet of gained altitude and if the temperature at sea level is 25 degrees what would the temperature at 35,000 feet be?

-45 degrees

Step-by-step explanation:

35,000 : 1000 = 35. This means 1000 feet will be gained 35 times. 35 * 2 = 70. This means 70 degrees will be lost as altitude increases. 25 - 70 = - 45. You start with 25, so you must subtract the temperature that is lost.