You have a bag containing red and blue marbles. If 60% of the marbles are red and you add 6 more blue marbles, the percent of red becomes 50%. How many marbles did you start with?
Category: Math · Difficulty: expert
Hint: Let the total number of marbles be x.
Answer
30
Explanation
Let x be the total number of marbles. Then 0.6x + 6 = 0.5(x + 6) leads to the solution x = 30.
This is a expert math riddle — one of the harder riddles here. The answer is 30.
More Math riddles
- I am formed when choices are made, and I can create many outcomes. What am I?
- I can be flat or curved, I can hold areas but have no volume. What am I?
- I can be found in every group, summing up what you need. What am I?
- I can define relationships, but I’m not something you can touch. What am I?
- I am a set of numbers that can be graphed, often in two dimensions, to show relationships. What am I?
- I can hold values and relationships, often needing specific rules to decipher. What am I?
- I can divide but never conquer, I exist in harmony with my kin. What am I?
- I can be played with numbers, yet I have no end. What am I?