SOLUTION: How many integers between 15 and 75 are not evenly divisible by 3?

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Question 1173052: How many integers between 15 and 75 are not evenly divisible by 3?
Answer by ikleyn(52914) About Me  (Show Source):
You can put this solution on YOUR website!
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From 15 to 75 inclusive, there are  75 - 14 = 61 integer numbers.


There are 20 gaps of the length 3 between 15 and 75;  hence, the number of integers in this interval  [15,75] 
that are multiple of 3 is  20 + 1 = 21.


The numbers that are not divisible by 3 are the rest  61 - 21 = 40 numbers.    ANSWER

Solved.