Answer:25 parts of water to be added in 5 parts of powder .
Explanation:
The ratio of powder to water required for a medicine is 1:5
If we have 5 parts of powder
To find : Parts of water to be added
Let x be the parts of water added when there is 5 parts of powder
Therefore we have
Powder 1 5
Water 5 x
Clearly, it is in direct variation
So we have

Hence, 25 parts of water to be added in 5 parts of powder.