brianlaw

Well, none of the digits can be 0 because the product is than going to be 0. You can't have more than 2 1's either.

To get started, we turn to the factorization of 10,000. It factors out as 2^4 * 5^4. This means that the only possible combinations of numbers are:

1,2,8,5,5,5,5 -> 7!/4! = 210 ways to arrange this

2,2,4,5,5,5,5 -> 7!/(4!*2!) = 105 ways to arrange this

1,4,4,5,5,5,5 -> 7!/(4!*2!) = 105 ways to arrange this

1,1,8,5,5,5,5 -> 7!/(4!*2!) = 105 wasy to arrange this

So the number of different possible codes is 120+105+105+105 = 435 possible codes.

Both are necessary for life.

Let's say all of them are $10 then the total is $470

$710 - $470 = $240

Because changing one $10 coin to a $20 coin adds $10,

There are 24 $20 coins

and 23 $10 coins

I think it is (x+2)^2 - 2

lets say one hour of work is x units of work

then it will take 3600 x to complete the project

then each person gets 3600 / 15 = 240 x

each person gets 240 hours

if each person does 8 x per day,

there will be 30 days needed

30 days / 5 days = 6 weeks

No, they dont

Sorry, I thought the three gymnasts were already deteremined

Convert 1/4 into 2/8

then add

answer is 3

3

Lets say the total is 48 units of work

Pipe A can do 6 units of work per hour

A and B combined can do 8 units of work per hour

B can then do 2 units of work per hour 

38/2 = 24

24 hours

19 is 10 + 9