All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Just Math
Microwave Math (Posted on 2005-11-08) Difficulty: 2 of 5
The keypad on my friend's microwave is broken: only one of the number keys (the N key) works. He found a workaround that allows him to cook for exactly 2 minutes, which is perfect for rewarming his giant cup of coffee. He does this by entering NN seconds, then start. He cooks for a period of time and then hits the pause button followed by N and start. (On his microwave, entering 99 would be the same as entering 139, since the 3rd number from the right is minutes)

For example, if N were "1", he could enter 11, cook until the display reads 6, pause, enter 1 (the display then reads 61), and cook for a total of 66 seconds. He also brags that using the same N key as above, but by pausing at a different time, he can cook for another whole number of minutes (other than 2).

Which number key is working on his microwave?

See The Solution Submitted by Larry    
Rating: 3.5000 (2 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re: And the winning number is... | Comment 6 of 8 |
(In reply to And the winning number is... by Bob Smith)

Other times available with only the 7 key working, and using a single or double press initially, and then a single press are given in the following table. The columns are the initial entry, the timed interval, the delay before pausing and the reading at the pause.














 7  0:14     7  0
 7  0:23     6  1
 7  0:32     5  2
 7  0:41     4  3
 7  0:50     3  4
 7  0:59     2  5
 7  1: 8     1  6
77  1:24    77  0
77  1:33    76  1
77  1:42    75  2
77  1:51    74  3
77  2: 0    73  4
77  2: 9    72  5
77  2:14    67 10
77  2:18    71  6
77  2:23    66 11
77  2:27    70  7
77  2:32    65 12
77  2:36    69  8
77  2:41    64 13
77  2:45    68  9
77  2:50    63 14
77  2:59    62 15
77  3: 4    57 20
77  3: 8    61 16
77  3:13    56 21
77  3:17    60 17
77  3:22    55 22
77  3:26    59 18
77  3:31    54 23
77  3:35    58 19
77  3:40    53 24
77  3:49    52 25
77  3:54    47 30
77  3:58    51 26
77  4: 3    46 31
77  4: 7    50 27
77  4:12    45 32
77  4:16    49 28
77  4:21    44 33
77  4:25    48 29
77  4:30    43 34
77  4:39    42 35
77  4:44    37 40
77  4:48    41 36
77  4:53    36 41
77  4:57    40 37
77  5: 2    35 42
77  5: 6    39 38
77  5:11    34 43
77  5:15    38 39
77  5:20    33 44
77  5:29    32 45
77  5:34    27 50
77  5:38    31 46
77  5:43    26 51
77  5:47    30 47
77  5:52    25 52
77  5:56    29 48
77  6: 1    24 53
77  6: 5    28 49
77  6:10    23 54
77  6:19    22 55
77  6:24    17 60
77  6:28    21 56
77  6:33    16 61
77  6:37    20 57
77  6:42    15 62
77  6:46    19 58
77  6:51    14 63
77  6:55    18 59
77  7: 0    13 64
77  7: 9    12 65
77  7:14     7 70
77  7:18    11 66
77  7:23     6 71
77  7:27    10 67
77  7:32     5 72
77  7:36     9 68
77  7:41     4 73
77  7:45     8 69
77  7:50     3 74
77  7:59     2 75
77  8: 8     1 76

  Posted by Charlie on 2005-11-08 11:29:30
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (6)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information