Positive Integers

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Positive Integers

by umaa » Wed Jul 29, 2009 7:59 am
How many positive integers less than 20 are either a multiple
of 2, an odd multiple of 7, or the sum of a positive multiple
of 2 and a positive multiple of 7 ?
(A) 19
(B) 18
(C) 17
(D) 16
(E) 15
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by shibal » Wed Jul 29, 2009 8:22 am
multiples of 2 less than 20: 2,4,6,8,10,12,14,16,18 (total: 9)
odd multiple of 7: 7 (total:1)
sum of a positive multiple of 2 and a positive multiple of 7: (2+7,4+7,6+7,8+7,9+7, 14+2, 14+4. total:7)

9+1+7=17

OA?

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by kaulnikhil » Wed Jul 29, 2009 9:27 am

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by umaa » Wed Jul 29, 2009 9:32 am
kaulnikhil, You're right. The answer is D. Can you explain how you got the answer?

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by PussInBoots » Wed Jul 29, 2009 10:09 am
The answer is 17: 2,4,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20

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by hariharakarthi » Wed Jul 29, 2009 10:18 am
multiples of 2 less than 20: 2,4,6,8,10,12,14,16,18 (total: 9)
odd multiple of 7: 7 (total:1)
sum of a positive multiple of 2 and a positive multiple of 7: (2+7,4+7,6+7,8+7,10+7, 12+7 total:6)

9+1+7=16

Ans 16

regards,
hhk

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by umaa » Wed Jul 29, 2009 12:34 pm
Got it. Thx.