Machines X and Y work at their respective constant rates. How many more hours does it take machine Y...

This topic has expert replies
Moderator
Posts: 2505
Joined: Sun Oct 15, 2017 1:50 pm
Followed by:6 members

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

Source: GMAT Prep

Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?

1) Machines X and Y, working together, fill a production order of this size in two-thirds the time that machine X, working alone, does.

2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does.

The OA is E
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 am
Location: Grand Central / New York
Thanked: 470 times
Followed by:34 members

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

BTGmoderatorLU wrote:
Tue Mar 10, 2020 12:07 pm
Source: GMAT Prep

Machines X and Y work at their respective constant rates. How many more hours does it take machine Y, working alone, to fill a production order of a certain size than it takes machine X, working alone?

1) Machines X and Y, working together, fill a production order of this size in two-thirds the time that machine X, working alone, does.

2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does.

The OA is E
Let's take each statement one by one.

1) Machines X and Y, working together, fill a production order of this size in two-thirds the time that machine X, working alone, does.

Say Machine X takes 3x hours, thus, machines X and y would take 2x hours. Say Machine Y takes y hours.

Thus, 1/3x + 1/y = 1/62x

y = 6x hours

Thus, Machine Y, working alone, would take 6x – 3x = 3x hours than Machine X, working alone; however, the value of x is not known. We can't get the answer.

2) Machine Y, working alone, fills a production order of this size in twice the time that machine X, working alone, does.

Certainly insufficient.

(1) and (2) together

Since Statement 2 gives the same result as Statement 1 gives, both statements together are insufficient.

The correct answer: E

Hope this helps!

-Jay
_________________
Manhattan Review

Locations: Manhattan Review Himayatnagar | GMAT Prep Hyderabad | GRE Prep Bangalore | Chennai GRE Coaching | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.