Answer
(a) The combined height of the buildings is 11,958 feet.
(b) The combined height is greater than 2 miles.
Work Step by Step
(a) Determine the combined height of all the building by adding together all the individual heights. Write the numbers in a column so that the ones digits are aligned. Beginning with the ones digit and then working to the left, add each column of numbers. For each result, write the ones digit of the result in the column being added and carry any leading digits to the next column and include in your addition for that column.
2717 + 1776 + 1667 + 1614 + 1483 + 1451 + 1250 = 11,958
(b) To determine whether the combined height is greater or less than 2 miles you must convert the height in feet to height in miles. You can do this by dividing the height in feet by the number of feet per mile, then comparing the result to 2 miles.
$11,958 \div 5280 = 2.26$
The combined height is $\approx$ 2.26 miles, which is greater than 2 miles.