Which bus?
By David Shaw, 13 June 2018
I caught a bus the other day with a very interesting number. Can you work out the number on the bus?
- It has four digits
- It’s less than 2000
- Its digits add up to 10
- If you reverse its digits, you get the same number (it’s a palindrome)
Scroll down for the answer!
Brainteaser answer
The bus I caught was number 1441.
Here’s one way to work it out:
- If it has four digits and it’s less than 2000, the first digit must be a 1.
- Since it’s the same forwards and backwards, the last digit must also be 1.
- Since all the digits together make 10, the middle two digits must add to eight.
- Since the number is the same forwards and backwards, the two middle digits must be the same, so they must both be 4.
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15 June, 2018 at 1:58 pm
I came up with 0550 which fits the bill except that it ends up having a leading zero, so I guess it’s not truly a four digit number. Bummer.
15 June, 2018 at 2:31 pm
Hi Greg,
I like your answer! Actually, I had a look around on the internet and found a bus with a leading zero:
https://www.123rf.com/photo_94740610_rostov-on-don-russia-january-2018-a-small-hyundai-bus-rides-along-route-number-40-through-the-street.html
So I reckon your answer is perfectly good!
16 June, 2018 at 10:36 pm
Look up the history of the number zero, very interesting. Both as a concept and a number. Greg is 100% right. A 4 digit number can most certainly begin with a zero as 0000 is a valid 4 digit number, just not a correct answer to this brainteaser. 0550 and 1441 are correct answers.
17 June, 2018 at 12:10 am
https://www.sciencedaily.com/releases/2018/06/180607141031.htm