Math Is Fun Forum

haiying

Guest

Hellllllp !!!!!

If you divide a number that is larger than 75 by a number that is less than 3, what can you tell about the relative value of the quotient? Explain your choice.
a. It must be greater than 25
b. It must be less than 25
c. It will be between 3 and 75.
d. There is not enough information to conclude any of the above.

I mean the answer is A. greater than 25 ????:o

gAr

Member

Registered: 2011-01-09

Posts: 3,482

Re: Hellllllp !!!!!

Hi,

"a number that is larger than 75" : consider 76
"a number that is less than 3" : consider 2 ( on the assumption it cannot take negative values)
Then the value of the quotient must be atleast 76/2 = 38.

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"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

soroban

Member

Registered: 2007-03-09

Posts: 452

Re: Hellllllp !!!!!

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haiying

Guest

Re: Hellllllp !!!!!

\text{Let }y \:=\:\text{number less than 3: }\:y \,<\,3 \quad\Rightarrow\quad \frac{1}{y} \,>\,\frac{1}{3}\;\;{\bf[2]}

I dont understand this part.....can someone explain more detail????????:o

haiying

Guest

Re: Hellllllp !!!!!

\text{Let }y \:=\:\text{number less than 3: }\:y \,<\,3 \quad\Rightarrow\quad \frac{1}{y} \,>\,\frac{1}{3}\;\;{\bf[2]}

I dont understand this part.....can someone explain more detail????????:o

I mean .....  y < 3   ----> 1/y > 1/3

I dont get ittt

Bob

Administrator

Registered: 2010-06-20

Posts: 10,649

Re: Hellllllp !!!!!

hi haiying,

gAr and soroban are using similar methods.

gAr picks particular numbers, 76 and 2, and shows the result is 38 which is bigger than 25

soroban uses 'greater than signs' > to do the same thing.

number that is larger than 75

so

number that is less than 3

so

In order to use > for both x and y, soroban takes the reciprocal of y and the reciprocal of 3 and reverses the sign from < to >

eg If 7 > 3 the 1/3 < 1/7.

so the second inequality becomes

Now put the two together by multiplying

Does that help you to understand it?

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

gAr

Member

Registered: 2011-01-09

Posts: 3,482

Re: Hellllllp !!!!!

Hi haiying,

I assumed the numbers to be positive integers. So concluded it to be atleast 38.

Hi bob and soroban,

Nice explanation.

Last edited by gAr (2011-02-27 22:29:59)

---

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

Bob

Administrator

Registered: 2010-06-20

Posts: 10,649

Re: Hellllllp !!!!!

hi gAr,

thanks, but it was soroban's answer.

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

gAr

Member

Registered: 2011-01-09

Posts: 3,482

Re: Hellllllp !!!!!

Yes, but I'd like to congratulate the team

---

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."

Bob

Administrator

Registered: 2010-06-20

Posts: 10,649

Re: Hellllllp !!!!!

You sound like a cricket player (or supporter)

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

gAr

Member

Registered: 2011-01-09

Posts: 3,482

Re: Hellllllp !!!!!

I used to be crazy about the sport at one time, but not anymore.
Now, it's only maths, so refreshing!!

---

"Believe nothing, no matter where you read it, or who said it, no matter if I have said it, unless it agrees with your own reason and your own common sense"  - Buddha?

"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."