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 [tex]2x+3x=20\rightarrow5x=20\rightarrow x=4[/tex]
So, the quantity of white paint in the mixture is [tex]2\times4=8[/tex] and the quantity of blue paint in the mixture is [tex]3\times4=12[/tex]
Now, to get the final ratio as 1:7, Mary should have [tex]7\times8=56 \text{ litres }[/tex] of blue paint. So, she need to add [tex]56-12=44 \text{ litres}[/tex].
Therefore, Mary has to add 44 litres of blue paint to the mixture to make the ratio as 1:7.
