Brain Teasers Optical Illusions Puzzle Hunts Codes & Ciphers Mechanical Puzzles
Personal Links
Browse Teasers
Search Teasers

Stacking CD's

Math brain teasers require computations to solve.


Puzzle ID:#37613
Fun:*** (2.19)
Difficulty:** (1.42)
Submitted By:The-stranger0Aus***




Andrew has a new 3 foot wide bookcase with two shelves, each 15 inches high. He plans to store his CD's on the shelves using new CD racks. Each CD rack is 17 inches wide and 7 inches high, and holds 3 stacks of 12 CD's.

Will Andrew have enough room for his 250 CD's in the bookcase if he uses the two shelves inside the bookcase and doesn't put any CD's on top of it? How many CD's will he be able to store?

Open Calculator


Drawing a diagram may be helpful.

What Next?


See another brain teaser just like this one...

Or, just get a random brain teaser

If you become a registered user you can vote on this brain teaser, keep track of
which ones you have seen, and even make your own.



Aug 01, 2007

Didn't need a calculator a little too easy for me OK teaser though
Aug 01, 2007

I love math so I got it fairly easy. But I thought it was a great teaser.
Aug 02, 2007

ah i havent done school in weeks,im not realy computing math right now, i might get it right in a couple of months when my brain is working again LOLZ
Aug 02, 2007

WOW i didnt even see the calculator,Im am so stupid LOLZ
Aug 03, 2007

I love math and the fact I didn't even need the clue! Loved it!
Aug 04, 2007

i love this kinda thing keep playin this one cause i loved it!!!!
Aug 05, 2007

Easy! But, by the way, you copied this from a Eduplace math challenge question.
Aug 12, 2007

A book*case* with two shelves in it, each 15" high (which I assume means the space between the shelf and whatever is above/below it), would be 45" high (+ the thickness of the shelves). You would be able to accommodate 288 CDs in a 3' bookcase with only one shelf; with two, there's room for 432.
Aug 13, 2007

This is a response to lldhund...
True, if there's 2 shelves in a bookcase, there would be 3 open spaces. Does this mean each space is 15 in high? No, we only know that 2 are. The last space could be 6 in high. Or 26. Maybe changing the question would make it clearer. Still liked it, though!
Jan 13, 2009

You didn't say all the CDs had to go in the racks, just that all have to go in the bookcase. Just using the two shelves you can store at least 306 CDs.

Given the dimensions of the racks, a CD can be at most 7/12 of an inch thick and 17/3 inches wide.

This means there is space on top of the second rack on each shelf to store one more CD high x 3 wide. On the end there is 2 inches to spare, which can accomodate at least 2 / (7/12) = 3 CDs standing on their sides. 15 inches tall means that at least two rows of CDs on the end are possible.

This gives

144 + 3x1 + 3x2 = 153 per shelf
or 306 total.

Back to Top

Online Now
13 users and 641 guests

Users In Chat
Follow Braingle!
Tap into all 20,000+ of our brain teasers, riddles and puzzles on your iPhone or iPad.
Braingle in the iTunes App Store
Copyright © 1999-2017 | FAQ | Widgets | Links | Green | Subscribe | Contact | Privacy | Conditions | Advertise | Braingle Time: 12:32 pm
Sign In Create a free account