General Contractor Practice Exam

To determine the number of risers needed for a staircase where the total elevation change is from 101 feet to 110 feet, the first step is to calculate the total vertical rise. This is done by subtracting the lower elevation from the higher elevation:

110 feet - 101 feet = 9 feet.

Now, we need to convert the total rise from feet to inches since the max riser height is given in inches. There are 12 inches in a foot, so:

9 feet x 12 inches/foot = 108 inches.

Next, we need to calculate how many risers are needed given that the maximum riser height is 7 inches. This is done by dividing the total rise in inches by the maximum riser height:

108 inches / 7 inches per riser = 15.4286...

Since the number of risers must be a whole number, we round up because partial risers cannot be constructed, hence we need 16 risers to accommodate the full elevation change while not exceeding the maximum riser height.

Therefore, the correct answer is that 16 risers must be installed on the southeast staircase, ensuring compliance with the riser height limitation while effectively covering the total rise.