# Math Is Fun Forum

Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫  π  -¹ ² ³ °

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## #426 2009-03-04 04:04:03

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#350. A person's is x[sup]th[/sup] in a row of n houses consecutively numbered 1, 2, 3, 4, 5, .... n. The sum of the numbers of the houses preceding his house is equal to the sum of the numbers following it. If x has the value 35, what is the value of n?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #427 2009-03-04 05:33:04

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

### Re: Brain Teasers

Last edited by JaneFairfax (2009-03-13 02:03:39)

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## #428 2009-03-04 16:34:30

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

Correct, JaneFairfax!

#351. In a party, all the guest shook hands with everybody else once except the host. The host had only 7 handshakes. How many guests were present at the party if the number of handshakes were 3 less than the least 4 digit number?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #429 2009-03-07 02:43:50

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#352. What is the value of

where n is a Natural number?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #430 2009-03-07 18:39:00

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#353. There are 4 oranges, 5 apples and 6 mangoes in a fruit basket. In how many ways can a person make a selection of fruits, from among the fruits in the basket?

#354. Ten points are marked on a straight line and Eleven points are marked on another line, parallel to the said straight line. How many triangles can be constructed with vertices among the above points?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #431 2009-03-08 01:24:08

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#355. a, b, and c are three positive numbers and

.
If (s-a) : (s-b) : (s-c) = 1 : 7 : 4, what is the ratio a:b:c equal to?

#356. If x:y = a:b = 1:5, then what is the value of

?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #432 2009-03-08 01:54:55

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#357. If each permutation of the digits 1, 2, 3, 4, 5, and 6 is listed in the increasing order of magnitude, what would the 289[sup]th[/sup] term be?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #433 2009-03-08 02:34:11

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

### Re: Brain Teasers

Why did the vector cross the road?
It wanted to be normal.

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## #434 2009-03-08 03:02:47

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

mathsyperson:-

#358. How many intgeres between 6000 and 6999 (both included) have atleast one of their digts repeated?

#359. How many natural numbers less than a million can be formed using the digits 0, 7, and 8?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #435 2009-03-12 03:31:16

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#360. How many successive zeros would the product

end in?

#361. If N = 2[sup]8[/sup] x 5[sup]3[/sup], how many sets of two factors of N are co-prime to each other?

#362. How many successive zeros would there be at the end of

?

#363. Find the last non zero digit of 96!.

#364.What is the number in the unit's place of

?

#365. The numbers from 1 to 33 are written side by side as follows:-

.
What is the remainder when this number is divded by 9?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #436 2009-03-13 02:03:05

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#366. How many successive zeros would there be at th end of the product

?

#367. How many successive zeros would there be at the end of the product

?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #437 2009-03-13 07:57:42

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#368. What is the value of

?

#369. What is the value of

?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #438 2009-03-13 20:10:57

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#370. What is the remainder obtained when 4[sup]96[/sup] is divided by 6?

#371. What is the remainder when (15[sup]23[/sup] + 23[sup]23[/sup]) is divided by 19?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #439 2009-03-13 20:14:37

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#372. what is the number in the unit's place of

?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #440 2009-03-15 07:15:23

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#373. What are the values of x, y, and z equal to if they are all natural numbers and

?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #441 2009-03-15 07:28:25

Devantè
Real Member
Registered: 2006-07-14
Posts: 6,400

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## #442 2009-03-15 07:31:13

Devantè
Real Member
Registered: 2006-07-14
Posts: 6,400

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## #443 2009-03-15 07:32:25

Devantè
Real Member
Registered: 2006-07-14
Posts: 6,400

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## #444 2009-03-15 21:16:08

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

Answers to #362, #365, and #372:-

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #445 2009-03-18 04:06:28

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#374. Let n∈N, N>25 and A, G, and H denote the Arithmetic Mean, Geometric Mean, and Harmonic Mean of 25 and n respectively. What is the smallest value of n such that A, G, and H are in the set
{25, 26, ........ n}?

#375. Two finite sets have m and n elements respectively. The total number of subsets of the frst set is 56 more than the total number of subsets of the second set. What are the values of m and n respectively?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #446 2009-03-19 09:43:52

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#376. Find the sum of all odd numbers of four digits which are divisible by 9.

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #447 2009-03-20 04:22:49

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#377. What is the value of

?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #448 2009-03-21 02:48:08

JohnnyReinB
Member
Registered: 2007-10-08
Posts: 453

### Re: Brain Teasers

"There is not a difference between an in-law and an outlaw, except maybe that an outlaw is wanted"

Nisi Quam Primum, Nequequam

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## #449 2009-03-21 05:47:07

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

That's not the correct answer, JohnnyReinB!

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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## #450 2009-03-22 23:11:49

Jai Ganesh
Registered: 2005-06-28
Posts: 43,599

### Re: Brain Teasers

#378. The difference between the fourth powers of two natural numbers is 12240. The difference between the squares of the two numbers is one-one hundred and seventieth part of the difference between the fourth power of the two numbers. What are the two possible differences between the two natural numbers?

It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.

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