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divisiblilty

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divisiblilty

by [email protected] » Thu Apr 09, 2009 5:06 am
How many integers are divisible by 3 between 10! and 10!+20 inclusive?



6
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by moutar » Thu Apr 09, 2009 6:24 am
There are 21 numbers between 10! and 10! + 20.

Every third number is divisible by 3.

Therefore there are 21/3 = 7 numbers divisible by 3 in the range.
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by PAB2706 » Sat Apr 11, 2009 12:41 am
how come there are 21 integers btwn 10! + 20 and 10!..

I thot there were 20 and thus i got answer as 6
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by mals24 » Sat Apr 11, 2009 3:42 am
The question says 10! and 10!+20 inclusive

The formula for number of integers between A and B inclusive = A - B + 1

Number of integers between 10! and 10!+20 inclusive
= 10! + 20 - 10! + 1
= 21 integers.
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