View All num of num See all Photos Cvent This employer has taken extra steps to respond to reviews and provide job seekers with accurate company information, photos, and reviews. Interested for your company?Learn More. www.cvent.com Employer Engaged Overview Reviews Salaries Interviews Jobs Photos Benefits 244 Reviews 237 Salaries 170 Interviews 108 Jobs Follow Add Review or Salary Follow Add Review or Salary Interview Question Software Developer Interview(Student Candidate) McLean, VA Cvent Brainteaser: 10 bags of coins. 1 bag has fake coins. Each normal coin weighs 10g. Each fake coin weighs 11g. Using one scale and one weighing, how do you find the fake bag of coins? Tags: See more , See less 8 Answer Add Tags Answer Interview Answer 1 Answer ▲ 3 ▼ Take 1 coin from the 1st bag, 2 coins from the 2nd bag, 3 coins from the 3rd bag, etc... and weigh them together. If there are 10 bags of normal coins, you know that the total weight would be S = (1+2+3+ ... + 10)I*10. If the fake bag is the 3rd bag, then the total weight would be 30 + S and you would know it's the 3rd bag. By looking at the difference between the total weight and S, you know which bag it is. Interview Candidate on Apr 28, 2012 Add Answers or Comments To comment on this, Sign In or Sign Up.