Question

Mary mixes white paint and blue paint in the ratio 2:3

Answer 1

Given:

Ratio of white and blue paint is 2:3

Total quantity of paint is 20 litres

To find:

Quantity of blue paint to be mixed so that the ratio of white paint to blue paint becomes 1:7

Solution:

The ratio 2:3 totals 20 that is $2x+3x=20\rightarrow5x=20\rightarrow x=4$

So, the quantity of white paint in the mixture is $2\times4=8$ and the quantity of blue paint in the mixture is $3\times4=12$

Now, to get the final ratio as 1:7, Mary should have $7\times8=56 \text{ litres }$ of blue paint. So, she need to add $56-12=44 \text{ litres}$.

Therefore, Mary has to add 44 litres of blue paint to the mixture to make the ratio as 1:7.