Suppose its a dry day and you are on top of a 15000 mountain

Suppose it’s a dry day, and you are on top of a 15,000’ mountain, and you measure T=- 12°C. Estimate the temperature at 3,500’ (deg C).

Solution

Temperature decreases by 1.95 C for every 1000 feet as we go up the mountain

now temp 15000 feet is -12 C

Temp at foot of mountain is -12 + 15 * 1.95 = 17.25

Hence temperature at 35000 is 17.25 - (3500*1.95 /1000) = 10.425