Math Is Fun Forum

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Brain Teasers

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

Answer to #60:

Your answer is correct, JaneFairfax! Very good!
Buth there's a minor mistake in how you arrived at the answer.

---

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.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Brain Teasers

Argh! I didn’t read the question carefully. Sorry, my mistake.

Last edited by JaneFairfax (2008-05-22 03:02:42)

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

---

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.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Brain Teasers

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

#63. A block of wood in the form of a cuboid 4" × 9" × 11" has all its six faces painted pink. If the wooden block is cut into 396 cubes of 1" × 1" × 1", how many of these would have pink paint on them?

---

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.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Brain Teasers

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Brain Teasers

---

igloo myrtilles fourmis

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Brain Teasers

---

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

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

Solution to #59:
You ought to be correct, JaneFairfax and John E Franklin!
But I had the series of side total of a magic square, commencing with a 3x3 magic square using number 1-9, in my mind!

Solution to #63:
Well done, mathsyperson!

---

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.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

#64. A snail creeps 9 ft up a wall during the daytime. After all the labor it does throughout the day, it stops to rest a while... but falls asleep!! The next morning it wakes up and discovers that it has slipped down 6 ft while sleeping.

If this happens every day, how many days will the snail take to reach the top of a wall 63 ft in height?

---

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.

John E. Franklin

Member

Registered: 2005-08-29

Posts: 3,588

Re: Brain Teasers

Last edited by John E. Franklin (2008-05-24 10:28:32)

---

igloo myrtilles fourmis

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

Answer to #64:
You are correct, John E. Franklin! Well done!

---

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.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

#65. Roland, Marc and Pierrette are three children in the same family.
Pierrette is three times Marc's age. In two years, she will be twice the age Roland will have at that time. Roland is a year older than Marc.
How old are the children?

#66. A person can carry sufficient food and water to travel four days in the desert. The planned trip will last six days. Alone, no one can succeed.
How many persons will it take to lead the first person to her destination and to allow the others to return to the starting point?

---

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.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Brain Teasers

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

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

Answers to #65 and #66:

Both of you are perfectly right, JaneFairfax and 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.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Brain Teasers

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

Answer to #29:

Very well done, JaneFairfax! Your answer is perfectly right!

#67. Divide $146 (in whole $ increments) into a number of bags so that I can ask for any amount between $1 and $146, and you can give me the proper amount by giving me a certain number of these bags without opening them. What is the minimum number of bags you will require?

---

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.

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Brain Teasers

---

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

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

Answer to #67:
What you think is right, mathsyperson! Well done!!!

---

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.

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

#68. If five persons can sew five dresses in five days,
how many persons can sew fifty dresses in fifty days?

#69. Monique is 24 years old. She is twice the age that Valerie was when Monique was the same age that Valerie is now. How old is Valerie?

---

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.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Brain Teasers

Jai Ganesh

Administrator

Registered: 2005-06-28

Posts: 48,461

Re: Brain Teasers

Answer to #68:
JaneFairfax, would you like another opportunity?

---

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.

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: Brain Teasers