Question

How many natural numbers below 660 are divisible by 5 and 11 but not by 3?

Answer 1

________________   8 _______________-

EXPLANATION 

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The 11 multiples of 55 which are less than 560, but of these 11 multiples some can be multiples of 3.

The numbers of such, multiples are the quotient of 11 / 3.= 3 

Out of 11 multiples of 55, 3 are multiples of 3. 

that is why 

                        less than 660 and divisible by 5 and 11 but not by 3=11−3= 8.