## Thursday, April 29, 2010

### Global Boiling

April 24th, Boston. Crazy weather forecast. Winter to Summer in three days. What single digit can one change so that the daily high temperatures displayed below are in an arithmetic progression?

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Anonymous said...

I'm not understanding the grammar of the question? Sorry. Tom

rachel_t said...

day 4 has a temperature of 82 degrees.

Then, there is 12 degree increase every day

Katrina said...

Rachel got it I believe - to specifically answer your question, change the 3 in a high of 83 on Friday to a 2.

Anonymous said...

I'm not understanding this grammar either. :)

Sorry,
Melissa

Maria said...

Tom, Melissa - you are right. I consulted with a native speaker and she told me that "can" and "one" should be switched in order for the sentence to be grammatically correct. So, instead of "What digit one can change..." it is "What digit can one change..." This is corrected now.

Thumbs up to Rachel_t and Katrina who managed to find the arithmetic progression anyway. Rachel_t gets a puzzle point for posting the answer first.

Anonymous said...

Ok. I finally understand the question. May I suggest the following wording? "What single digit can one change so that the daily high temperatures displayed below are in an arithmetic progression?"

The low temperatures cannot be put into arithmetic progression by the change of a single digit.

Thanks for the puzzles.

Maria said...

Suggestion accepted!

Anonymous said...

There is another answer. You can change the 46 to 47, then the progression of daily highs increase will be 11, 12, and 13.

Maria said...

Like the last answer. Original sequence of high temperatures: 46, 58, 70, 83. Change 46 to 47, get 47, 58, 70, 83. While it is not an arithmetic progression, temperature differences do make an arithmetic progression:
58-47=11
70-58=12
83-70=13

Brave, anonymous.