Brain Teasers
Lines and Dots
If 2 lines and 4 dots equals 14 and 3 lines and 2 dots equals 17, what does 1 line and 3 dots equal?
2 lines + 4 dots = 14
3 lines + 2 dots = 17
1 line + 3 dots = ?
2 lines + 4 dots = 14
3 lines + 2 dots = 17
1 line + 3 dots = ?
Answer
8This is Mayan math. A line represents 5, a dot represents 1, and a shell represents 0 (place holder.)
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Comments
Fun, simple algebra. Nice intro to Mayan math!
easy. got it right without thinking of mayan math.(witch i have heard of)
can anyone show me the process by this given?
2x + 4y = 14
3x + 2y = 17
1x + 3y = ?
2x + 4y = 14
3x + 2y = 17
1x + 3y = ?
joe613-
While there is no single way, many start something like this:
Triple the first statement and double the second, then find the difference.
6x + 12y = 42
6x + 4y = 34
----------------
0x + 8y = 8
While there is no single way, many start something like this:
Triple the first statement and double the second, then find the difference.
6x + 12y = 42
6x + 4y = 34
----------------
0x + 8y = 8
Why triple and double?
First I did :
2L +4D=14
Divide all that by 2 and get:
L+2D=7
L=7-2D
But then I was stuck. So I tried:
3L+2D=17
+ 2L+4D=14
---------------
5L+6D=31
But I'm stuck again
First I did :
2L +4D=14
Divide all that by 2 and get:
L+2D=7
L=7-2D
But then I was stuck. So I tried:
3L+2D=17
+ 2L+4D=14
---------------
5L+6D=31
But I'm stuck again
no need to use any equation. i don't even know the mayan math but i got it right it's easy..
2 common methods to solve systems of equations:
**First, substitution**
2L + 4D = 14
3L + 2D = 17
Solve for L in the first equation
2L = 14-4D
L = 7 - 2D
Substitute this for L in the 2nd equation
3L + 2D = 17
3(7-2D) + 2D = 17
21 - 6D + 2D = 17
21 - 4D = 17
-4D = -4
D = 1
Put 1 for D in either equation to solve for L
2L + 4D = 14
2L + 4(1) = 14
2L = 10
L = 5
*Second, combining equations*
2L + 4D = 14
3L + 2D = 17
----------------
We want to add these two to have one term fall out (equal zero), so let's multiply the second by -2
2L + 4D = 14
3L + 2D = 17(-2)
2L + 4D = 14
-6L - 4D = -34
----------------
-4L = -20
L = 5
Substitute to solve for D
2(5) + 4D = 14
10 + 4D = 14
4D = 4
D = 1
Good teaser
**First, substitution**
2L + 4D = 14
3L + 2D = 17
Solve for L in the first equation
2L = 14-4D
L = 7 - 2D
Substitute this for L in the 2nd equation
3L + 2D = 17
3(7-2D) + 2D = 17
21 - 6D + 2D = 17
21 - 4D = 17
-4D = -4
D = 1
Put 1 for D in either equation to solve for L
2L + 4D = 14
2L + 4(1) = 14
2L = 10
L = 5
*Second, combining equations*
2L + 4D = 14
3L + 2D = 17
----------------
We want to add these two to have one term fall out (equal zero), so let's multiply the second by -2
2L + 4D = 14
3L + 2D = 17(-2)
2L + 4D = 14
-6L - 4D = -34
----------------
-4L = -20
L = 5
Substitute to solve for D
2(5) + 4D = 14
10 + 4D = 14
4D = 4
D = 1
Good teaser
Very easy.
Use addition/subtraction method to combine equations. Find a value for what lines are and then solve for what dots are.
Use addition/subtraction method to combine equations. Find a value for what lines are and then solve for what dots are.
I already knew how the Mayan math system worked, so this one wasn't really much of a teaser, but I liked it anyway!!!
im really good at mayan math. Not a very helpful life skill though.
though i dont know mayan math I got it right by using simultaneous linear equations
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