Quote:
Originally Posted by krsh.vik Dude 61 = 20*2 + 9 + 2*6
79 = 20*2 + 9 + 6*5
Solution :
6 mod 6 = 0 which means all multiples of six are possible
9 mod 6 = 3 which means all numbers of the form 6x+3 >= 9 are possible
20 mod 6 = 2 6x+2 >= 20 are possible
29 mod 6 = 5 6x+5 >= 29 are possible
40 mod 6 = 4 6x+4 >= 40 are possible
49 mod 6 = 1 6x+1 >= 49 are possible
answer is 43  |
That's right ...
This following could have been a better way.
Each number can be represented as 3x, 3x+1 or 3x+2.
9-6 mod 3 = 0 and 6 mod 3 = 0 means all 'n' of form 3x are possible for 3x>=6
Since 6 and 9 are both multiples of 3, 'n' of form 3x+1 and 3x+2 will have atleast a 20 in them.
20 mod 3 = 2 means all 'n' of form 3x+2 are possible for 3x+2>=26
20*2 mod 3 = 1 means all 'n' of form 3x+1 are possible for 3x+1>=46
The maximum possible value of number not possible is of form 3x+1 and is less than 46 i.e. 43.
Another problem.
How many ways are there to express 1000000 as a product of exactly three integers greater than 1? (For the purpose of this problem, abc is not considered different from bac, etc.)