Answer:
90grams
Explanation:
Total rabbits to be pulled out=13
Each rabbits weighs 600 grams
If the magician already pulled out 3,
He has a total of 13-3 more rabbits to be pulled out.
13-3=10 rabbits
If the magician needs 9 grams of magic dust for each rabbits.
How much more magic dust will he need?
Recall, he already pulled out 3, so he has 10 more rabbits remaining.
Total magic dust needed=9 grams×10 rabbits
=90 grams.
The magician needs 90 grams more magic dust to complete his task.