Can you form 24 using all the numbers 3, 3, 9, and 11, along with any of the 4 arithmetic operations (addition, subtraction, multiplication, and division) and parentheses?
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This is traditionally the Game of 24, with numbers ranging from 1 to 13 inclusive. If you pick 4 integers from 1 to 13 at random to set up a puzzle, the probability is approximately 75% that there will be a solution. Source .
Going by the "24 game" rules, you would do:
1 1 − 3 ⇒ 8 × 9 ⇒ 7 2 ÷ 3 = 8 = 7 2 = 2 4
I maintain that my ‘no’ answer was correct for me. Before seeing a solution, I could NOT solve the puzzle.
Nice source link. I wonder what if the % of solutions that do not contain 1 are higher or lower than 75%. Surely combinations without 2 or without 3 must be lower than 75%. I may have to try to get this into Excel or something to play around with it.
That's much nicer than the solution I had. I thought this would be much harder than my previous one, but turns out to be the same.
Nice solution. ⌣ ¨
How would you have known to do that?
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I missed it because I was just focusing on addition, subtraction, and multiplication, forgetting multiplication. Once I saw the solution, I realized that division could remove the extra factor of 3.
In the ordering of solutions shown, there is a tendency for the first one shown to be upvoted, and the remaining to not be looked at. This suggests that the solutions should be shown in reverse order so that the least upvoted be shown first.
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Good point. It would probably be even more fair if the answers were posted in random order, but I will give Brilliant staff the benefit of the doubt and assume that they have considered all the ordering options and went with what they felt was the most "workable" option.
The problem should have stated "using all those numbers once and no other numbers."
That's pretty great, but I've got a better one: TREE(9) / TREE(3) ^11↑↑↑↑↑↑↑3 = 24
Nice! But brackets wasn't mentioned in the question. And hence, proceeding by BODMAS, this fails.
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But brackets wasn't mentioned in the question
No it was mentioned. ''Parentheses'' means ( )
( 1 1 − ( 9 / 3 ) ) × 3 = 8 × 3 = 2 4 .
That's the one I was thinking of :)
(11χ9)-9-(3χ11)-(3χ11)=24
But we can use each number only once, right?
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The numbers are 3,3,9,11
In this solution they HAVE only been used once each.
No powers/exponents
Exponents weren't allowed, but I don't think we should crush outside-the-box thinking. Brilliant solution! Keep bending the rules, it's the best way to nurture your creativity!
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Agreed! Sometimes not following the rules leads to novel solutions. To me this seems to be the hallmark of mathematical exploration throughout history.
But it’s the most creative solution
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It's not a solution to the problem specified. If someone asks you how to light a fire using nothing but two pieces of wood, and you tell them to simply use a lighter, have you really solved anything?
My solution also...though it doesn't exactly stick to only the four arithmetic signs, since there is an exponent involved.
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THE SOLUTION REQUIRES AN EXPONENT WITH IS NOT SPECIFICALLY ALLOWED.
You've gone beyond arithmetic
It is true that exponents were not specified as permitted. However, this solution did impress me.
Exponents aren't allowed.
No indices
((11-3) x 9) ÷ 3 = (8 x 9) ÷ 3 = 72 ÷ 3 = 24
That's my solution also! Making an extra 3 out of 11 and 9 was too straightforward to see with a naked eye, haha!
3 x 9 = 27
27 - 3 = 24
24 + 1 - 1 = 24
Only kidding :) . the real method :
( 9/3 ) x ( 11 - 3) = 3 x 8 = 24
Since 72 / 3 = 24, we need to use the remaining 3 numbers, 3,9,11, to arrive at 72. Thus, 11 - 3 = 8, & 9 * 8 = 72.
((11 - 3) * 9) / 3 = 24
why not do it the easy way? (9 + 11 + 3 + 3) - (11 - 9) = 24
Excellent. Simple and, in the spirit of the problem, uses each number only once.
(11-3)*9 = 72 ; 72/3 = 24
(11-3)(9)=72, so, (72÷3)=24
Too many 3's
The question asked us to use ALLof the numbers.
Where is 11?
The problem should mention that you use each number only once.
You can work out the problem methodically without depending on hit and trial by the following thought process: keep one of the numbers aside , let it be 3 . The following operations can be performed with the number 3 in order to get the result as 24 -> 1. 21+3 2. 27-3. 3. 8x3 4. 72/3 . By checking each option it is observed that only 3. And 4. Are feasible . You can get the 4th option by: ((11-3)x9)/3 . The 3rd option is obtained by: (9/3)x(11-3)
((11 - 3) x 9) / 3 = 24
11 - 9 = 2
3 + -3 = 0
11(11 - 9) = 22
11(11 - 9) + 11 - 9 + 3 + -3 = 24
Here is way to do it but I don't know of a general test for it besides showing an example.
( 1 1 − 3 ) × 3 9 = 2 4
While not to the rules ... (11-9)^3 x 3 😊
(11-3)x9/3=8x9/3=72/3=24
LaTeX: 1 1 3 × ( 9 − 3 ) = 4 × 6 = 2 4
(11-3)*(9/3) = 24
((11-3) x 9)) / 3 = (8 x 9) / 3 = 72 / 3= 24
Looking at the others, my solution is complicated, but not nearly as complicated as some things on this site. (11-3)/3 9=24 11-3=8 8/3= 3 8 3 8 9= 3 7 2 3 7 2 =72/3=24
(11-3)/39=24 <------- This is an incorrect statement. It does mean what you think it does. It is actually meaningless. Fix it with this: ((11-3)/3)9=24
There are too many 3s.
6+11=17 not 27
((11 X 3)+(9 x 3)+ (9 + 3))/ 3=(33 + 27 + 12)/3=72/3=24
(11 - 3) X ( 3 9 ) = 8 X 3 = 24
You cannot use 4.
You cannot use 4.
Wrong. ( 1 1 × ( 3 ÷ 3 ) ) − 9 is equal to 2 not 24.
9 / ( 3 / (11 - 3 ) ) = 9 / ( 3 / 8) = 24
It says can you form 24 using the four numbers and using any of the four operands and parentheses, of which I found two methods at deriving twenty-four: (11-3)(9÷3)=24, or 9(11-3)/3=24
If you don't have to use all 4 you can just do this: 11 x 3 - 9 = 24
If not: [(11 - 9) ^ 3] x 3
Exponents aren't allowed.
3 9 equals 3
11 minus 3 equals 8
8 times 3 equals 24
Going by the prime factorization of 24.
24 = 2x2x2x3 i.e. 2^3 x 3.
24 = (11-9)(11-9)(11-9) x 3 or
24 = (11-9)^3 x 3.
Exponents are not allowed.
24=8x3 and 11-3 = 8, so (11-3)x(9/3) = 24
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( 9 ÷ 3 ) × ( 1 1 − 3 ) = 3 × 8 = 2 4 .