number properties

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by rijul007 » Mon Jan 30, 2012 8:50 pm
No of numbers divisible by 3 = 66
No of divisible by 21 = 9

NUmbers divisible by 3 but not divisible by 7 = 66-9 = 58

Option C

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by Anurag@Gurome » Mon Jan 30, 2012 8:53 pm
sud21 wrote:Image
Number of multiples of x in the given range = [(Last multiple of x in the given range - First multiple of x in the given range)/x] + 1
Here, number of multiples of 3 in the given range = (198 - 3)/3 + 1 = 66
and number of multiples of 7 in the given range = (189 - 21)/21 + 1 = 9
So, required number of integers = 66 - 9 = 57

The correct answer is B.
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