Question

In a bag,There are red and blue cubes in the ratio 4:7.I add 10 more red cubes to the bag.Now here are red and blue cubes in the ratio 6:7.How many blue cubes are in the bag?

Answer 1

Given:

The ratio of red and blue cubes is 4:7.

After adding 10 more red cubes the ratio of red and blue cubes is 6:7.

To find:

The number of blue cubes.

Solution:

The ratio of red and blue cubes is 4:7.

Let the number of red and blue cubes be 4x and 7x respectively.

After adding 10 more red cubes.

Number of red cubes = 4x+10

Then, the ratio of red and blue cubes is 6:7.

$\dfrac{4x+10}{7x}=\dfrac{6}{7}$

$7(4x+10)=6(7x)$

$28x+70=42x$

$70=42x-28x$

$70=14x$

Divide both sides by 14.

$5=x$

Now,

Number of blue cubes in the bag is

$7(5)=35$

Therefore, the number of blue cubes is 35.