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# If A + B = 5, B + C = 4, and C + D = 6, then AB + CD + AC + BD is:

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Senior Manager
Joined: 30 Sep 2017
Posts: 253
Concentration: Technology, Entrepreneurship
GMAT 1: 720 Q49 V40
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WE: Engineering (Real Estate)
If A + B = 5, B + C = 4, and C + D = 6, then AB + CD + AC + BD is:  [#permalink]

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Updated on: 08 Aug 2019, 16:02
2
1
00:00

Difficulty:

25% (medium)

Question Stats:

80% (02:30) correct 20% (02:43) wrong based on 44 sessions

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If A + B = 5, B + C = 4, and C + D = 6, then AB + CD + AC + BD is:

A) 11
B) 12
C) 15
D) 28
E) 48

+1 kudo only if you like the question

Originally posted by chondro48 on 07 Aug 2019, 11:45.
Last edited by chondro48 on 08 Aug 2019, 16:02, edited 2 times in total.
Intern
Joined: 10 May 2018
Posts: 34
Re: If A + B = 5, B + C = 4, and C + D = 6, then AB + CD + AC + BD is:  [#permalink]

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07 Aug 2019, 12:03
1
1
AB + CD + AC + BD
=> B(A+D) + C(A+D)
= (B+C)(A+D)

From the given equaation:
A + B -(B + C)+C + D = 5 - 4 + 6

A+D=7

therefore

(B+C)(A+D)
=4*7
=28
Ans D
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Joined: 19 Jun 2019
Posts: 32
Re: If A + B = 5, B + C = 4, and C + D = 6, then AB + CD + AC + BD is:  [#permalink]

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07 Aug 2019, 23:07
1
No constraints on $$A$$, $$B$$, $$C$$ or $$D$$.

So, let $$A=5$$, $$B=0$$, $$C=4$$ and $$D=2$$.
$$\implies AB+CD+AC+BD = 28$$

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Re: If A + B = 5, B + C = 4, and C + D = 6, then AB + CD + AC + BD is:   [#permalink] 07 Aug 2019, 23:07
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