# Word Problem's

G

#### Guest

##### Guest
In how many ways can 3 girls divide 10 pennies if each must en dup with at least one penny?

I need a step by step help with this problem ;
An office building has 33 floors, each 10 feet high, and elevators that travel at a constant speed. If it takes 10 seconds for an elevator to go from the first floor to the fifth floor, how long will it take an elevator to go from the fifth floor to the middle floor?

#### stapel

##### Super Moderator
Staff member
1) Does order matter? That is, would A getting 1, B getting 2, and C getting 7 be different from A getting 7, B getting 1, and C getting 2?

2) Hints: How many seconds does it take to go from one floor to another? Which is the middle floor?

Eliz.

G

#### Guest

##### Guest
From the first floor it takes 10 seconds. so that means that it takes 20secs from the first to the 10th , ghe middle floor is the 17th floor

#### Gene

##### Senior Member
Start by giving one manditory penny to each. That leaves 7 to be handed to 3 girls. There are 8 (N=0 to 7) ways to give pennies to girl A. There are 8-N ways to give pennies to girl B. There is 1 way to give the rest to girl C. Since each of the N ways for girl A gives 8-N for girl B I get sum<sub>N=0 to 8</sub> of (8-N)= 36 ways.
No guaranties on that, but it seems right to me. I would say that 4,4,2 is different than 4,2,4. I'm sure girls B & C would agree.

Look at your elevator again. How many floors between 1st and 5th? Between 1st and 10th? Between 5th and 17th?

#### Denis

##### Senior Member
Agree with yor shrewd penny handling, Gene:
0 0 7
0 1 6
0 2 5
...
6 1 0
7 0 0