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

Redeem

If a certain wheel turns at a constant rate of \(x\)

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Moderator
Posts: 2505
Joined: Sun Oct 15, 2017 1:50 pm
Followed by:6 members

If a certain wheel turns at a constant rate of \(x\)

by BTGmoderatorLU » Sat Jun 29, 2019 6:18 am

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Source: GMAT Prep

If a certain wheel turns at a constant rate of \(x\) revolutions per minute, how many revolutions will the wheel make in \(k\) seconds?

A. \(60kx\)

B. \(kx\)

C. \(\frac{x}{k}\)

D. \(\frac{x}{60k}\)

E. \(\frac{kx}{60}\)

The OA is E
Top
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pm
Location: Vancouver, BC
Thanked: 5254 times
Followed by:1268 members
GMAT Score:770

by Brent@GMATPrepNow » Sat Jun 29, 2019 7:50 am
BTGmoderatorLU wrote:Source: GMAT Prep

If a certain wheel turns at a constant rate of \(x\) revolutions per minute, how many revolutions will the wheel make in \(k\) seconds?

A. \(60kx\)

B. \(kx\)

C. \(\frac{x}{k}\)

D. \(\frac{x}{60k}\)

E. \(\frac{kx}{60}\)

The OA is E
We can solve the question using equivalent ratios

Wheel turns at a constant rate of x revolutions per minute
We can also say the wheel turns at a constant rate of x revolutions per 60 seconds
In other words, # of revolutions/seconds elapsed = x/60

How many revolutions will the wheel make in k seconds?
Let R = the number of revolutions will the wheel make in k seconds
We can now write: x/60 = R/k
To solve for R, we can first cross multiply to get: 60R = kx
Divide both sides by 60 to get: kx/60

Answer: E
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8086
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

by Scott@TargetTestPrep » Sat Jul 06, 2019 4:58 pm
BTGmoderatorLU wrote:Source: GMAT Prep

If a certain wheel turns at a constant rate of \(x\) revolutions per minute, how many revolutions will the wheel make in \(k\) seconds?

A. \(60kx\)

B. \(kx\)

C. \(\frac{x}{k}\)

D. \(\frac{x}{60k}\)

E. \(\frac{kx}{60}\)

The OA is E
Since k seconds is k/60 minutes, the wheel will make x * k/60 = xk/60 revolutions in k seconds.

Alternate Solution:

We can create a proportion: "x revolutions is to 60 seconds as q revolutions is to k seconds," and our goal is to solve for q:

x/60 = q/k

xk = 60q

xk/60 = q

Answer: E

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
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8086
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

by Scott@TargetTestPrep » Sat Jul 06, 2019 4:58 pm
BTGmoderatorLU wrote:Source: GMAT Prep

If a certain wheel turns at a constant rate of \(x\) revolutions per minute, how many revolutions will the wheel make in \(k\) seconds?

A. \(60kx\)

B. \(kx\)

C. \(\frac{x}{k}\)

D. \(\frac{x}{60k}\)

E. \(\frac{kx}{60}\)

The OA is E
Since k seconds is k/60 minutes, the wheel will make x * k/60 = xk/60 revolutions in k seconds.

Alternate Solution:

We can create a proportion: "x revolutions is to 60 seconds as q revolutions is to k seconds," and our goal is to solve for q:

x/60 = q/k

xk = 60q

xk/60 = q

Answer: E

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
Top
Post new topic Post Reply
• Page 1 of 1