At a distance 4 miles west of town, oil-bearing deposits are found 3231 feet deep. Also, 6 miles west of town, the oil is found 3416 feet down. Assuming the oil-bearing stratum lies on a straight line,
How deep would you expect to drill 8 miles west of town in order to find oil?
A) 3416 feet
B) 3416.1 feet
C) 3601.17 feet
D) 3601 feet

Question

Quizplus · Accepted Answer

The depth of the oil deposits increases linearly as you move west of town. To find the rate of change in depth per mile, we can use the two given points: (4 miles, 3231 feet) and (6 miles, 3416 feet). The slope (rate of change) is (3416 - 3231) / (6 - 4) = 185 / 2 = 92.5 feet per mile. Starting from 6 miles west at 3416 feet, moving 2 more miles west (to 8 miles) at 92.5 feet per mile increase gives: 3416 + (2 * 92.5) = 3416 + 185 = 3601 feet.

At a Distance 4 Miles West of Town, Oil-Bearing Deposits