Answer:

15M

Explanation:

6M weigh as much as 3P

6C is the same as 2P


So to balance 30C

we have to

2P x 5 (5 is from 6 x 5 = 30C) = 10

and add 5 more since

6M weigh as much as 3P

and 6C is equal only to 2P

So the final answer is -

15M will balance 30C