School-Safe Puzzle Games

## Math Brainteaser- Marbles and Rocks

Grandma gave Eli a box containing equal numbers of marbles and rocks. After Eli rolled 36 marbles away, there were 3 times as many rocks as marbles.  How many marbles were there to begin with?

This can be solved without any formal algebra training. Answers can be submitted below, will reveal before the week is over!

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### 12 Comments to “Math Brainteaser- Marbles and Rocks”

1. Falwan | Profile

++++++++++++++++++++++++++++++++++++++++++++++++

54 MARBLES = 54 ROCKS

++++++++++++++++++++++++++++++++++++++++++++++++

2. DoodleFish | Profile

54 marbles

starting with equal numbers of rocks and marbles, then have 3x as many rocks as marbles => 2/3 of the marbles were rolled away.

36 x 1.5 =54

3. engjs1960 | Profile

36/2 = 18 + 36 = 54.

4. Hendy | Profile

54 marbles = 54 Rocks
54 – 36 = 18
18 * 3 = 54

5. Shawn | PUZZLE GRANDMASTER | Profile

But I like algebra!

m=marbles
r=rocks
m=r

When you take away 36 of the marbles, you are left with 1/3 of the original number of marbles.

(m-36)*3=m

m=54

6. suineg | PUZZLE MASTER | Profile

Ok, I think without algebra could be solved like this:
Intially the proportion were 1::1 , when you substract 36 marbles the proportion goes 1::3
so 2/3 =36 so 1/3 = 18 so initially you have 54 marbles… now that i think about it there was no equation right, so it must be valid for a non algebraic solution, cool.

7. Hex | PUZZLE MASTER | Profile

solve x=3(x-36)
x=54 marbles

8. BlindCupid | Profile

48.

36 / 3 = 12
12 x 4 = 48

9. prof | Profile

36/2=18*3=54

10. RogHyde | Profile

Before: 54 marbles and 54 rocks
After: 18 marbles and 54 rocks