Problem 1909. Two fractions, one sum
Given a positive number x, write a MATLAB script that will tell you how many ways that the reciprocal of that number can be written as a sum of two reciprocals of integers. For example, 1/10 can be written as:
- 1/11 + 1/110
- 1/12 + 1/60
- 1/14 + 1/35
- 1/15 + 1/30
- 1/20 + 1/20
The order of the fractions does not matter, so 1/11+1/110 is the same as 1/110+1/11. Therefore, two_fractions(10)=5. You do not need to output the fraction pairs themselves, only the total number of sums. Good luck!
Solution Stats
Problem Comments
-
5 Comments
Although people have solved this already. I'm sure that there's an error in the 7th test suite.
two_fractions(10^7) = 113;
two_fractions(10^8) = 165;
two_fractions(two_fractions(10^7) + two_fractions(10^8)) ==> two_fractions(278) = 5 ==> not 14
Nick, I see where your problem is: two_fractions(10^8) is not 165. You are running into rounding errors on some of your larger fractions.
Ok Thanks. I'll have a look.
http://www.wolframalpha.com/input/?i=%28x%2By%29*5+%3D+x*y
Nice problem!
Solution Comments
Show commentsProblem Recent Solvers13
Suggested Problems
-
Back to basics 6 - Column Vector
1062 Solvers
-
28 Solvers
-
Find Index of maximum Value and maximum Value of a vector
162 Solvers
-
Find the solution of algebraic equation
51 Solvers
-
Sum the 'edge' values of a matrix
343 Solvers
More from this Author80
Problem Tags
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!