# a box of paper

• Sep 7th 2008, 05:30 AM
busyboy
a box of paper
A box contains 25 slips of paper numbered 1 to 25. What is the probability that one will randomly select a number that is divisible by 3 or 7?
help me anybody.....
I'll be very appresiate you!(Happy)
• Sep 7th 2008, 05:51 AM
mr fantastic
Quote:

Originally Posted by busyboy
A box contains 25 slips of paper numbered 1 to 25. What is the probability that one will randomly select a number that is divisible by 3 or 7?
help me anybody.....
I'll be very appresiate you!(Happy)

Write out all the numbers between 1 and 25 that are divisible by either 3 or 7. Count how many there are. Divide that number by 25. Viola!
• Sep 7th 2008, 10:53 AM
Moo
Quote:

Originally Posted by mr fantastic
Viola!

(Crying)

Jhevon made the same mistake !
It's voilą (Tongueout)
Viol...means rape ! but don't worry, I would give my consent xD
• Sep 7th 2008, 11:07 AM
Shyam
Quote:

Originally Posted by busyboy
A box contains 25 slips of paper numbered 1 to 25. What is the probability that one will randomly select a number that is divisible by 3 or 7?
help me anybody.....
I'll be very appresiate you!(Happy)

A number divisible by 3 is = 3, 6, 9, 12, 15, 18, 21, 24
= total 8 numbers.

A number divisible by 7 is = 7, 14, 21
= total 3 numbers.

Probability that a number divisible by 3 or 7 is $= \frac {8+3}{25}$

$= \frac {11}{25}$
• Sep 7th 2008, 11:25 AM
Plato
Quote:

Originally Posted by Shyam
A number divisible by 3 is = 3, 6, 9, 12, 15, 18, 21, 24
= total 8 numbers.

A number divisible by 7 is = 7, 14, 21
= total 3 numbers.

Shyam, if you are going to simply handout complete solutions at least do them correctly.
Probability that a number divisible by 3 or 7 is $= \frac {8+3{\color{red}-1}}{25} = \frac {10}{25}$
You counted 21 twice.
• Sep 7th 2008, 03:42 PM
mr fantastic
Quote:

Originally Posted by Moo
(Crying)

Jhevon made the same mistake !
It's voilą (Tongueout)
Viol...means rape ! but don't worry, I would give my consent xD

The viola is my favourite instrument. I like to hear it sometimes (Tongueout) when I post. Hence my deliberate transposition of letters. As for Jhevon, I think he's just lousy at French (Rofl) (Rofl)