Elevator & Floor Tiles Q's.?

Question

Hello everyone, got two brain teasers for ya. Please show your work, Enjoy!


1. "Elevator"

The capacity of an elevator is either 20 children or 15 adults. If 12 children are currently in the elevator, how many adults can still get in?

2. "Floor Tiles"

How many 9-inch-square floor tiles are needed to cover a rectangular floor that measures 12 feet by 15 feet?

Answer 1

These are fairly simple, I think, but rather than just give you the answer, I'll give you a clue in each case:

For the elevator, if 20 children = 15 adults, how many adults is each child worth?
(it's going to be less than one, obviously)
Once you know that, you can figure out how many adults 12 children are worth. Then just figure out how many more adults you can add to equal 15 in total.

For the floor tiles, if the floor is 12' by 15', that's how many inches by how many inches? Multiply length by width, and that gives you the area in inches. Now what is the area of a 9" by 9" floor tile? You get that the same way. (9x9)
Now just divide the floor area in inches by the tile area in inches, and you have the number of tiles you need.

Good luck!

update: ah, nevermind, guess you got the answers without having to think. Oh well... you can at least check to see if the answer provided above is accurate or not using this method. :)

Answer 2

The assumption must be that a child weighs 75% as much as an adult.

12 children is 60% of the total capacity (12/20)
the remaining 40% could be adults.
40% of 15 adults is 6 adults.

Each floor tile is .75 feet x .75 feet = .5625 feet
a 12x15 floor is 180 sq feet.
180/.5625 = 320 tiles.

Answer 3

2 adults
2880tile

Answer 4

1- 6
2- 320
;))