What is the total number of positive integers that are less than 400 and that have no positive factor in common with 400 other than 1?	Choose the correct choice from the following choices
A) 100  B) 120  C) 150  D) 160  E) 180
Since 400=2^4*5^2 then a number can not have 2 and/or 5 as a factor.   The odd numbers do not have 2 as a factor and there are 200 odd numbers from 1 to 400.   We then need to eliminate the 40 numbers that end with 5, that is 5, 15, 25,...,395.   There are a total of 200 - 40= 
<gadget id="calculator">200 - 40</gadget>
<output>160</output>
160 such numbers between 1 and 400.   The answer is 160.
<result>D</result>
What is the total number of positive integers that are less than 400 and that have no positive factor in common with 400 other than 1?