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# Find the value of 5a + 10b, if a and b are positive int

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Manager
Joined: 13 May 2017
Posts: 103
Location: Finland
Concentration: Accounting, Entrepreneurship
GMAT 1: 530 Q42 V22
GPA: 3.14
WE: Account Management (Entertainment and Sports)
Find the value of 5a + 10b, if a and b are positive int  [#permalink]

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10 Oct 2018, 09:35
1
00:00

Difficulty:

45% (medium)

Question Stats:

62% (01:13) correct 38% (01:32) wrong based on 26 sessions

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Find the value of 5a + 10b, if a and b are positive integers such that a > b and the product of a and b is prime.
(1) 100<100a<300
(2) ab is even
Director
Joined: 19 Oct 2013
Posts: 508
Location: Kuwait
GPA: 3.2
WE: Engineering (Real Estate)
Re: Find the value of 5a + 10b, if a and b are positive int  [#permalink]

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10 Oct 2018, 09:45
1
rencsee wrote:
Find the value of 5a + 10b, if a and b are positive integers such that a > b and the product of a and b is prime.
(1) 100<100a<300
(2) ab is even

From the question stem we know that a * b = prime

the only way to get a prime if one of the variables is 1 and the other is a prime (2,3,5 etc..)

Statement 1) can be rewritten as 1 < a < 3

As a result we know a > b so a = 2 and b = 1. Sufficient

Statement 2) it says a*b = even

The only even prime is 2 and a > b so a = 2

Sufficient.

Re: Find the value of 5a + 10b, if a and b are positive int   [#permalink] 10 Oct 2018, 09:45
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