I got asked these 2 Mental Math Questions during a M&A Interview, how do I actually solve them in my head?
Today I had my first ib interview which went pretty well until these 2 brainteasers came up and showed my lack of mental math skills:
What is 3 to the power of 12 What is 5 to the power of 5.
No way I could do these in my head
3^(2* 6)=9^(2* 3)=81^3= approx 80^3=6400*80=Approx > 512000
25* 25* 5=625*5=3125
So when somthing like 3 to the power of 12 comes up, I basically am not expected to calculate the exact number but rather approximate? Thank you!
I mean I wouldn't know how to do 81* 81* 81 in my head, just saying what I would say in an interview
Math major here. I always try this approach when I do those numbers in my head:
3^12 = (3^4)^3. Now 3^4 is 81, and you want 81^3. 81^3 = 81 * 81 * 81 = (80+1) * (80+1) * (80+1) In your head, it not hard to do (80 + 1) * (80 + 1) = 80^2 + 80 + 80 + 1 = 6561. The hard part is 6561 * 81. Try the same way above. 6561 * 81 = (6560 + 1) * (80 + 1) = 6560 * 80 + 6560 + 80 + 1. Now 6560 * 80, do 656 * 8 first. then put two 00s there. Then do the sum.
5^5 is easier. 25 ^ 2 = 625, 625 * 5 = 3125. Maybe I cheated, because as a Math major we are kinda supposed to know this one.
Hope this helps.
I am being honest here. I wouldn't be able to pull this off in my head without confusing the numbers
Alright. How did u answer the question during the interview?
http://arithmetic.lemo.education/ and learn. Mental math is an absolut classic in finance interviews, so just learn it. No big deal about it.
Sequi et ducimus quam nobis vel vel corrupti. Aut voluptatem qui sint doloribus ullam quisquam ut. Nulla non pariatur est dolore.
Iusto doloremque dolor ratione. Vel sint perspiciatis sint sapiente. Error qui id occaecati distinctio aut fuga sed nobis.
See All Comments - 100% Free
WSO depends on everyone being able to pitch in when they know something. Unlock with your email and get bonus: 6 financial modeling lessons free ($199 value)
or Unlock with your social account...