BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

In the racetrack shown above, regions I and III are semicircular with radius r. If region II is rectangular and its...

Expert replies
by AAPL » Mon Nov 02, 2020 4:18 am

Timer

00:00

Answers

A

B

C

D

E

Stats

Difficulty

Official Guide
2019-04-26_1746.png
In the racetrack shown above, regions I and III are semicircular with radius r. If region II is rectangular and its length is twice its width, what is the perimeter of the track in terms of r?

A. \(2r(\pi+2)\)
B. \(2r(\pi+4)\)
C. \(2r(\pi+8)\)
D. \(4r(\pi+2)\)
E. \(4r(\pi+4)\)

OA B
Join the discussion
Source: — Problem Solving |

AAPL wrote:
Mon Nov 02, 2020 4:18 am
Official Guide

2019-04-26_1746.png

In the racetrack shown above, regions I and III are semicircular with radius r. If region II is rectangular and its length is twice its width, what is the perimeter of the track in terms of r?

A. \(2r(\pi+2)\)
B. \(2r(\pi+4)\)
C. \(2r(\pi+8)\)
D. \(4r(\pi+2)\)
E. \(4r(\pi+4)\)

OA B
Solution:

We see that the width of the rectangle = diameter of the semicircle = 2r, and the length of the rectangle = 4r.

The perimeter of the track consists of the circumference of one circle and twice the length of the rectangle in the middle. Therefore, the perimeter of the track is:

2πr + 2 x 4r2πr + 8r = 2r(π + 4)

Answer: B

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Join the discussion