copying machines problem

Expert replies

gmat009: Master | Next Rank: 500 Posts; Posts: 458; Joined: Sun Aug 31, 2008 10:44 amFollowed by: 1 member; Thanked: 3 times

by gmat009 » Tue Oct 07, 2008 12:33 pm

If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?
(1)One of the machines produces copies at the constant rate of 250 copies per minute.
(2)One of the machines produces copies at twice the constant rate of the other machine.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

Source: Beat The GMAT — Data Sufficiency | Tue Oct 07, 2008 12:33 pm

cubicle_bound_misfit: Master | Next Rank: 500 Posts; Posts: 246; Joined: Mon May 19, 2008 7:34 am; Location: Texaco Gas Station; Thanked: 7 times

by cubicle_bound_misfit » Tue Oct 07, 2008 12:50 pm

the answer is E.

stmt 1. Does nor talk about other machine.

stmt 2.

in 5 minutes it will produce 5/2 *x copies where x is the speed of slower machine.

together

we are not sure if x = 250
and the other machine is 125 or 500

hence E.

Cubicle Bound Misfit

farooq: Master | Next Rank: 500 Posts; Posts: 140; Joined: Sat Feb 28, 2009 8:51 amFollowed by: 3 members; Location: India; Thanked: 14 times

by farooq » Tue Dec 15, 2009 9:34 am

gmat009 wrote:If two copying machines work simultaneously at their respective constant rates, how many copies do they produce in 5 minutes?
(1)One of the machines produces copies at the constant rate of 250 copies per minute.
(2)One of the machines produces copies at twice the constant rate of the other machine.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
D. EACH statement ALONE is sufficient.
E. Statements (1) and (2) TOGETHER are NOT sufficient.

Two machine can be M1 and M2.

How many copies will these machines produce in 5 min?

A: M1 or M2 produces 120 copies/min. we only have an information of one machine. Insufficient.

B: information about numbers of copies is missing.

M1/M2=120

From second statement, M1=2M2 or M2=2M1.

Lots of Ambiguities. Therefore, E is the right answer.

Test takers love to frames such questions

Regards,
Farooq Farooqui.
London. UK

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