In the set of positive integers from 1 to 80, what is the sum of all the odd multiples of 5? Choose the correct answer:	A) 180	B) 245	C) 320	D) 260	E) 270
reduce to 1 - 80   5 - 15 - 25 - 35 - 45--55--65--75 are valid multiples. Add them --&gt; 320   320
<result>C</result>
In the set of positive integers from 1 to 80, what is the sum of all the odd multiples of 5?