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# Does nm =40? (1) 10/n = m/4 (2) 5n = 20 and 8m = 80

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Does nm =40? (1) 10/n = m/4 (2) 5n = 20 and 8m = 80  [#permalink]

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Updated on: 08 Nov 2018, 04:18
1
00:00

Difficulty:

5% (low)

Question Stats:

89% (00:33) correct 11% (00:40) wrong based on 290 sessions

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Does nm =40?

(1) 10/n = m/4
(2) 5n = 20 and 8m = 80

a) 10/n = m/4
if we consider different signs of n & m
nm=40 or nm=-40
NS

b) 5n=20 => n=4
8m = 80 =>m=10
=> nm=40 ---Sufficient

Guys do we need to consider that a) is providing ratio so we don't need to consider -ve signs.

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The proof of understanding is the ability to explain it.

Originally posted by GMATD11 on 01 May 2012, 01:29.
Last edited by Bunuel on 08 Nov 2018, 04:18, edited 4 times in total.
Edited the question
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Joined: 02 Sep 2009
Posts: 55801
Re: Does nm =40? (1) 10/n = m/4 (2) 5n = 20 and 8m = 80  [#permalink]

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01 May 2012, 01:44
Does nm =40?

(1) $$\frac{10}{n} = \frac{m}{4}$$--> cross multiply $$40=mn$$. Sufficient. So, as you can see we have only one value for $$mn$$

(2) 5n = 20 and 8m = 80 --> $$n=4$$ and $$m=10$$ --> $$mn=40$$. Sufficient.

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Re: Does nm =40? (1) 10/n = m/4 (2) 5n = 20 and 8m = 80  [#permalink]

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31 Oct 2018, 10:58
gmatbusters wrote:
Does nm =40?
(1) $$\frac{10}{n} = \frac{m}{4}$$
(2) 5n = 20 and 8m = 80

1. Cross multiplying, we get mn = 40
2. Shows that n =4 and m = 10. mn = 40

D
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Joined: 05 Dec 2018
Posts: 1
Re: Does nm =40? (1) 10/n = m/4 (2) 5n = 20 and 8m = 80  [#permalink]

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10 Jan 2019, 19:53
Bunuel wrote:
Does nm =40?

(1) $$\frac{10}{n} = \frac{m}{4}$$--> cross multiply $$40=mn$$. Sufficient. So, as you can see we have only one value for $$mn$$

(2) 5n = 20 and 8m = 80 --> $$n=4$$ and $$m=10$$ --> $$mn=40$$. Sufficient.

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Re: Does nm =40? (1) 10/n = m/4 (2) 5n = 20 and 8m = 80   [#permalink] 10 Jan 2019, 19:53
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