John took a test that had 60 questions numbered from 1 to 60. How many of the questions did he answer correctly?
This is a DS question from GMAT OG12
(problem 29) but I was hoping to get some assistance with a specific part of solving the question not the actual solution itself.
My question is how do you determine the number of odd numbers as well as the number of even numbers in a data set? I am aware that there are 30 odd and 30 even in this data set (60 questions from 1 to 60) but what if I had a data set from like 34-101 questions (how would i solve for the number of odd numbers and even numbers)? I seem to remember a number property formula to easily do this but cant recall what it was. Thanks for your help!