How many even number in the range between 10 to 170 inclusive are not divisible by 3  Choose the correct choice:
A) 15	B) 30	C) 31	D) 33	E) 54
We have to find the number of terms that are divisible by 2 but not by 6( as the question asks for the even numbers only which are not divisible by 3)   For 2,   10,12,14...170   using AP formula, we can say 170 = 10 + (n-1) *2   or n=81.   For 6,   12,18,...168   using AP formula, we can say 168 = 12 + (n-1) *6   or n=27.   Hence, only divisible by 2 but not 3 = 81-27= 
<gadget id="calculator">81-27</gadget>
<output>54</output>
54. hence, Answer 54
<result>E</result>
How many even number in the range between 10 to 170 inclusive are not divisible by 3