Brain Teasers
Balance Board Blues
At the balance board, a teacher has set up a problem for her students. Using the information provided on the table below, can you determine how many C's you need to balance the "A" on Scale 4? A, B, and C denote different weights.
Scale 1: 1L balances 1C+1A
Scale 2: 1B+1C balances 1A
Scale 3: 3B balances 2L
Scale 4: 1A balances ?C
Scale 1: 1L balances 1C+1A
Scale 2: 1B+1C balances 1A
Scale 3: 3B balances 2L
Scale 4: 1A balances ?C
Answer
You need 5C.1. If you double the weights on Scale 1, you learn that 2L = 2C + 2A.
2. By checking out Scale 3 you know that you can replace 2L in the above equation with 3B: 3B = 2C + 2A.
3. Add 3C to each side. Now 3B + 3C = 5C + 2A.
4. By checking Scale 2, you can replace each C + B with A: 3A = 5C + 2A.
5. Subtract 2A from both sides, and get A = 5C.
Hide Answer Show Answer
What Next?
View a Similar 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.
Solve a Puzzle
This brain teaser has no comments.
To post a comment, please create an account and sign in.
Follow Braingle!