Question

A bag contains 150 marbles. Some are blue, and the rest are white. There are 21 blue marbles for every 4 white marbles. How many blue marbles are in the bag? Explain your reasoning.

Answer 1

Given:

Total number of marbles in the bag = 150

There are 21 blue marbles for every 4 white marbles.

To find:

The number of blue marbles in the bag.

Solution:

Since, there are 21 blue marbles for every 4 white marbles, therefore the ratio of blue marble to white marbles is 21:4.

Let the number of blue marbles be 21x and white marbles be 4x.

Total number of marbles in the bag = 150

`21x+4x=150`

`25x=150`

Divide both sides by 25.

`x=(150)/(25)`

`x=6`

Now,

`\text{Blue marbles}=21x`

`\text{Blue marbles}=21(6)`

`\text{Blue marbles}=126`

Therefore, the number of blue marbles is 126.