Login
Discover
Waves
Decks
Plus
Login
Signup
Kelvin Koo
@kelkoo
25
A year 2 student from The University of Hong Kong :)
Followers
214
Following
39
Resource Credits
Available
Used
Location
Hong Kong
Created
June 5, 2017
RSS Feed
Subscribe
Comments
Blog
Posts
Comments
Communities
Wallet
kelkoo
mathematics
2017-06-30 11:30
RE: Brainsteem #9 Prize Maths Puzzle [Win 40% and 10% in SBD]
so m+n= 137
$ 0.000
0
kelkoo
mathematics
2017-06-30 11:29
RE: Brainsteem #9 Prize Maths Puzzle [Win 40% and 10% in SBD]
4 number from 1-9 sum up to 17: 1259 1268 1349 1358 1367 1457 2348 2357 2467 (9 combinations) or 4 number from 1-9 sum to 28: 9874 9865 (2 combinations) The probability= [11* (4!*5!)]/9! =11/126
$ 0.000
0
1
kelkoo
mathematics
2017-06-28 18:54
RE: Brainsteem Quickfire Q4 [Win 40% and 10% in SBD]
It would be easier to start with cube, as there is only 5 3-digit cubes (i.e. 125,216,343,512,729). Note that 1 Across and 2 Down is cube. There is two possible solution pair: 125 with 512 or 512 with
$ 0.000
0
kelkoo
mathematics
2017-06-25 10:34
RE: Brainsteem Quickfire Q3 [Win 2 SBD + 1 SBD]
The smallest possible sum (a+b)= 36+45=81 1/20= 1/a+1/b= (a+b)/ab --> 20(a+b)=ab b=20a/(a-20)=20+400/(a-20) Hence a+b=a+20-400/(a-20), By differentiation, a+b is minimized when (a-20)^2=400, i.e. a=40,
$ 0.000
1
kelkoo
quiz
2017-06-16 14:20
RE: QUIZ Test #11 - can you solve this? difficulty level: medium
Yes, they will be free for sure! If number 1 see that 2 and 3's hat is of the same color, number 1 will guess his hat right. If number 1 cannot make a guess, number 2 should know that his hat is different
$ 0.000
0
kelkoo
chainbb-general
2017-06-15 14:13
RE: [Free Steem!] Mathematics × Programming Competition #1
Answer submitted :)
$ 0.032
2
1
kelkoo
contest
2017-06-08 02:32
RE: $$$ Free Steem!!! Puzzle Contest #2 $$$
I am participating.
$ 0.000
1
1
kelkoo
math
2017-06-06 07:55
RE: Math challenge #4 - Probability of slapping your Chief Executive?
My answer is 0.07446 :)
$ 0.000
3
1
