Question

A bag contains 150 marbles. The ratio of blue to white is 21 to 4. How many blue marbles are in the bag? Explain your thinking using the triple number line.

Answer 1

Answer: 126 blue marbles

Explanation:

We don't know how many marbles there are, so we can call it x. 21 of a certain number of blue marbles, plus 4 of a certain number of white marbles is 150.

1. Make an equation: 21x+4x=150

2. Simplify. 25x=150

3. Divide to both sides. x=6

4. Plug in 6 to the ratio. 21 x 6=126 blue marbles

Answer 2

126

Explanation:

Blue : White = 21 : 4

(ratio of Blue/ sum of ratio) * total marbles

This gives us the number of blue marbles

so:

21/25 * 150 = 126

Therefore the total number of blue marbles is 126