209k views
10 votes
A bag contains 3 blue, 4 red and 3 yellow marbles. How many blue marbles must be added to the bag for it to contain 75% blue marbles?

User Tarfa
by
7.4k points

1 Answer

9 votes

Answer:

18

Explanation:

Note that 75% = 75/100 = 3/4, so 3/4 of the marbles must be blue. Let x be amount of blue marbles added. We can write an equation using this.

75% = 3/4 = (3 + x blue marbles)/(3 + 4 + 3 + x total marbles) = (3+x)/(10+x)

Multiplying by 4(10 + x) on both sides:

3(10 + x) = 4(3+x)

30 + 3x = 12 + 4x

18 = x

Therefore, we must add 18 blue marbles for 75% of the marbles to be blue.

I hope this helps! :)

User Sameera Sy
by
8.3k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories