Get Active in Our Amazing Community of Over 463,000 Peers!

Schedule mock interviews on the Meeting Board, join the latest community discussions in our Consulting Q&A and find like-minded Case Partners to connect and practice with!

Case Math

Math problem
Recent activity on May 12, 2019
3 Answers
1.8 k Views
Anonymous A asked on May 11, 2019


in an interview I had to solve a problem, which ws conceptually easy, however, to get to total sales I had to solve this: 2*480*360*16*365*0.7

This is perfectly doable, but took me some time. How would you go about it in terms of simplifying and rounding?


Overview of answers

  • Upvotes
  • Date ascending
  • Date descending
Best answer
replied on May 12, 2019
McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School


4 skills might be used here:

  • Get used to round up and down (but ask the interviewer if that's ok)
  • Learn how to multiply double digit numbers (
  • Learn the division table up to 1/11 (i.e. 5/6 = 83.3)
  • Get used to working with zeros using the powers of 10 (Hint: 4000000 = 4*10ˆ6)


Was this answer helpful?
Anonymous C replied on May 11, 2019

Round: 2 x 500(rounded up) x 400(rounded up) x 16 x 300(rounded down to compensate for previous roundings) x 0.7 = 1.34B. The precise answer is 1.41B, so it's within 10%.

Was this answer helpful?
Anonymous B replied on May 11, 2019

My guess is you need to estime the result rougthly and not go through hard computation. The idea here is to round the numbers

2*48*10*36*10*16*365*0.7 ~ 96*10*36*16*360*7 ~ 100*10*36*36*10*16*7 ~ 10^4*1296*112 ~ 10^5*1296*11~10^5*13*100*11~143*10^7. So rougthly speaking 1.4 billion

Was this answer helpful?
Vlad gave the best answer


McKinsey / Accenture Alum / Got all BIG3 offers / Harvard Business School
Q&A Upvotes
186 Reviews
How likely are you to recommend us to a friend or fellow student?
0 = Not likely
10 = Very likely
You are a true consultant! Thank you for consulting us on how to make PrepLounge even better!