Little Texas Drilling Company has three wells, each producin

This topic has expert replies
Moderator
Posts: 7187
Joined: Thu Sep 07, 2017 4:43 pm
Followed by:23 members

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Little Texas Drilling Company has three wells, each producing oil at a constant rate. Well A produces one barrel every two minutes. Well B produces one barrel every three minutes. Well C produces one barrel every four minutes. How many hours does it take Little Texas Drilling Company to produce 165 barrels of oil?

(A) 2
(B) 3
(C) 4
(D) 18
(E) 180

OA B

Source: Magoosh

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Sun Jan 06, 2019 3:48 am
Given the answer choices, the prompt should read as follows:
BTGmoderatorDC wrote:Little Texas Drilling Company has three wells, each producing oil at a constant rate. Well A produces one barrel every two minutes. Well B produces one barrel every three minutes. Well C produces one barrel every four minutes. How many hours does it take Little Texas Drilling Company to produce 185 barrels of oil?

(A) 2
(B) 3
(C) 4
(D) 18
(E) 180
A's rate = (1 barrel)/(2 minutes) * (60 minutes)/(1 hour) = 30 barrels per hour.
B's rate = (1 barrel)/(3 minutes) * (60 minutes)/(1 hour) = 20 barrels per hour.
C's rate = (1 barrel)/(15 minutes) * (60 minutes)/(1 hour) = 15 barrels per hour.
Since the combined rate for A+B+C = 30+20+15 = 65 barrels per hour, the time to produce 185 barrels = w/r = 185/65 = 3 hours.

The correct answer is B.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

Legendary Member
Posts: 2218
Joined: Sun Oct 29, 2017 2:04 pm
Followed by:6 members

by swerve » Sun Jan 06, 2019 1:25 pm
The three rates of production are 0.5 barrels/min , 0.33 barrels/min & 0.25 barrels/min.

Let's consider the answer choices:

The total number of barrels produced in

A) 2 hrs = 60+40+30 = 130
B) 3 hrs = 90+60+45 = 195

Hence B

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 7222
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

by Scott@TargetTestPrep » Sun Jan 27, 2019 6:27 pm
BTGmoderatorDC wrote:Little Texas Drilling Company has three wells, each producing oil at a constant rate. Well A produces one barrel every two minutes. Well B produces one barrel every three minutes. Well C produces one barrel every four minutes. How many hours does it take Little Texas Drilling Company to produce 165 barrels of oil?

(A) 2
(B) 3
(C) 4
(D) 18
(E) 180

OA B

Source: Magoosh
If we let t = the time in minutes during which the wells work together, we can create the following equation to determine t:

(1/2)t + (1/3)t + (1/4)t = 195

Multiplying the entire equation by 12, we have:

6t + 4t + 3t = 2340

13t = 2340

t = 2340/13 = 180 minutes, or 3 hours.


Alternate solution:

Since well A produces one barrel every two minutes, it can produce 30 barrels in an hour. Likewise, since well B produces one barrel every three minutes and well C produces one barrel every four minutes, they can produce 20 and 15 barrels an hour, respectively. Thus, in one hour, these 3 wells can produce 30 + 20 + 15 = 65 barrels. Thus, it takes them 195/65 = 3 hours to produce 195 barrels.

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