Jolene began building a picket fence by planting stakes in a row; the stakes were evenly spaced. After planting the

[BTGmoderatorDC]

Jolene began building a picket fence by planting stakes in a row; the stakes were evenly spaced. After planting the first 10 stakes, Jolene measured the length of the row and found that the row was 27 feet long. She continued the row by planting another 10 stakes, then measured the length of the entire row. How many feet long was the row of stakes Jolene had planted?

(A) 37
(B) 54
(C) 57
(D) 60
(E) 81


OA C

Source: Princeton Review

[Scott@TargetTestPrep]

Jolene began building a picket fence by planting stakes in a row; the stakes were evenly spaced. After planting the first 10 stakes, Jolene measured the length of the row and found that the row was 27 feet long. She continued the row by planting another 10 stakes, then measured the length of the entire row. How many feet long was the row of stakes Jolene had planted?

(A) 37
(B) 54
(C) 57
(D) 60
(E) 81


OA C

Solution:

Since there are 10 stakes, there are 9 spacings between a pair of consecutive stakes. Since the stakes are evenly spaced, each spacing is 27/9 = 3 feet. When Jolene plants 10 more stakes, there are 20 stakes and 19 spacings. Therefore, the row of stakes is 19 x 3 = 57 feet long.

Answer: C

[swerve]

Jolene began building a picket fence by planting stakes in a row; the stakes were evenly spaced. After planting the first 10 stakes, Jolene measured the length of the row and found that the row was 27 feet long. She continued the row by planting another 10 stakes, then measured the length of the entire row. How many feet long was the row of stakes Jolene had planted?

(A) 37
(B) 54
(C) 57
(D) 60
(E) 81


OA C

Source: Princeton Review

\(10\) picket fence will produce \(9\) gaps
length of each gap \(= \dfrac{27}{9} = 3\) feet

\(20\) pickets will produce \(19\) gaps. Length of each gap \(= 3\) feet

Therefore, total length \(= 19\cdot 3 = 57\) feet