Yesterday, Integrated Learning posted a 700 level GMAT question on our blog. Today, they have followed up with the answer:
To solve this question quickly, we need to know how to sum consecutive numbers quickly.
The process, as we teach all our students, is the following:
1. Find the middle number by averaging the endpoints:
(37 + 5)/2 = 21
2. Find the number of numbers. When we are including both the first and last number, subtract the endpoints and add 1:
(37 – 5) + 1 = 33
21×33 = 693
Now find the prime factors of 693. You will see that they are 3, 3, 7, 11.
Thus, the lowest prime factor is 3.
Integrated Learning provides professional, experienced GMAT tutors throughout the United States.