Answer:
1kg ghee is left behind
Explanation:
Here, we are to calculate the amount of ghee left.
Firstly, 2/4 was consumed for preparing medicine. This is same as 1/2
The amount used in preparing medicine is thus 1/2 * 20kg = 10kg
amount remaining = 20kg - 10kg = 10kg
She also use 2/5 and 1/2 of the remainder.
The total amount used is 2/5 + 1/2 = 9/10
The amount used is thus 9/10 * 10 = 9kg
what is left is thus 10kg -9kg = 1 kg