A bag of marbles has twice as many blue marbles as green marbles, and the bag has at least 57 marbles in it. At least how many green marbles does it have?
A) At least 38 green marbles
B) At least 29 green marbles
C) At least 19 green marbles
D) At least 20 green marbles

Question

Quizplus · Accepted Answer

Let the number of green marbles be $g$ and blue marbles be $2g$. The total number of marbles is at least 57, so $g + 2g \geq 57$, which simplifies to $3g \geq 57$. Dividing both sides by 3 gives $g \geq 19$, meaning there are at least 19 green marbles.

A Bag of Marbles Has Twice as Many Blue Marbles