How many positive numbers are in a sequence of z numbers, if the sequence alternates between positive and negative numbers and z is an odd number. The sequence starts with a negative number.  Choose the most appropriate option:  A) (z-1)/2  B) z/2  C) z/(2-1)  D) (z+1)/2  E) z/(2+1)
Lets put values for z, say z=7 since it's odd   and first number is neg so sequence will be {neg,pos,neg,pos,neg,pos,neg} we can see that it has 3 negative terms   so putting z=7 in the options,   option (z+1)/2 = (z-1)/2 =&gt; 7-1/2 = 4 , the number of positive integers   So, (z+1)/2 is the answer
<result>D</result>
How many positive numbers are in a sequence of z numbers, if the sequence alternates between positive and negative numbers and z is an odd number. The sequence starts with a negative number.