# Which number should come next? 144 ,121, 100, 81, 64 __?

Malaysia
February 9, 2007 10:48am CST
a. 17 b. 19 c. 36 d. 49 e. 65
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32 responses
• Malaysia
9 Feb 07
49
2 people like this
• Malaysia
10 Feb 07
me 49 too
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• United States
24 Feb 07
i agree 49 duhhhh
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@AJMSmith (112)
9 Feb 07
For a polynomial of order less than 5 49 is the only fit. For an order 5 polynomial fit, ANY of the alternatives given could fit. In fact a 5th order polynomial fit can be found for 144,121,100,81,64,u where u is any value you care to choose. Consider this. A 5th order polynomial is of the form ax^5 + bx^4 + cx^3 + dx^2 + ex + f. 6 unknowns. a unique solution is a certainty for ANY value of u.
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• India
20 Mar 07
49 for sure
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@sarawaken (360)
• Malaysia
10 Feb 07
Here I also have one question for you: 1,4,9,16,25,36,49.......what is the sum of the 100 terms of this number pattern?
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• India
20 Mar 07
we may use 100(100+1)(2*100+1)/6 So the answer is 338350 :)
@tomoko (36)
• Malaysia
9 Feb 07
solve this : 2x + 6 = 30, find the value of x.
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@rkalia73 (240)
• India
11 Feb 07
x has value 12 2x+6 = 30 = 2x = 30-6 = 24 = 2x = 24 = x = 24/2 = x=12
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@kliksini (85)
• Singapore
16 Mar 07
i love 49 ... yeaaa.. lookin me :)
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@elginkoh (89)
• Singapore
24 Feb 07
The next number should in the square root of 7. That is (d)49.
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@lraplove (30)
• China
23 Feb 07
D.49 Because: 144=12times12 121=11times11 ...... 64=8times8 ?=7times7 Right??
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• India
22 Feb 07
Well lets look into this: 144-121=23 121-100=21 100-81=19 81-64=17 64-?=15 Definitely 49 There's an other simpler way 12^2=144 11^2=121 10^2=100 9^2=81 8^2=64 7^2=? This way also its 49.
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• Bangladesh
16 Feb 07
Well, as it is solved already What is the next problem? But let me give you one puzzle. Can you prove from 1=1 to 1=2
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• Pakistan
13 Feb 07
It shoud be defintely 49 you took it this way: 144-121=23 121-100=21 100-81=19 81-64=17 and then the last number 64-(__)=15 that is 64-49=15 49 should be the perfect match for this problem continuing the series of odd numbers from 23-15
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• Pakistan
12 Feb 07
Well The numbers are detecting By last-2. Or The Square Of the previous Number. So the next One Will be 49!!!
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@yueliu (1621)
• China
12 Feb 07
I choose d 49.144-121=23,121-100=21,100-81=19,81-64=17. So look 23,21,19,17~~haha~~the next is 15. 64-15=49.
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@rkalia73 (240)
• India
11 Feb 07
Answer is 49. Because it is a series of perfect squares in decresing order starting from 12, 11, 10, 9, 8 and after this it should be square of 7. Which is 49. hence answer is 49.
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@kutchi (12326)
• Pakistan
11 Feb 07
well my answer is d.49 because the next difference should be 15
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• India
11 Feb 07
49 dear as u will subtract 15 from 64
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@sarawaken (360)
• Malaysia
10 Feb 07
is this a number sequences? my answer is 49 because 144 is perfect square of 12, 121 is perfect square of 11, 100 is perfect square of 10, 81 is perfect square of 9, 64 is perfect square of 64, so perfect square of 7 is 49. correct!!!!!
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@mythmoh (3986)
• United States
10 Feb 07
it should be 49,36,25,16,9,4,1.they are in the form of squares but in the descending order of numbers.
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• Singapore
10 Feb 07
49
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@sum_19 (56)
• India
10 Feb 07
The answer is 49.
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@ryanbgico (258)
• Philippines
10 Feb 07
The correct answer is 49, and that's from the choices letter "d". Well it is an arithmetic progression with numbers having differences of also arithmetic progressing odd numbers starting 23, 21, 19, 17, and 15. Well, you have made a unique discussion. I believe you are fond of mathematics. For me, its been a routine exercises when I studied Civil Engineering in my college years. Now that I am a Professional Civil Engineer already, its a great recall of those tricky math problems you have just posted. You are definitely unique. Hear you around my friend.
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