Change of rate
We are given the initial altitude of an airplane of 5,000 feet and the rate of descending at 150 feet per minute.
This means every minute the airplane loses part of its initial altitude.
If the airplane descends 150 feet per minute, then after 10 minutes, it has descended 150 * 10 = 1,500 feet.
Since we are not required to calculate the current altitude of the plane, but it change of altitude, we can say: The integer that represents the airplane's change of altitude after 10 minutes is 1,500
