Answer:
12
Step-by-step explanation:
You would multiply each kilogram amount by 2.2 to get the point equivalent.
The blank box should be equal to 4
The answer is 3
Multiply 6 by 3 to get the total amount of money for the books then minus the answer 18 which you get from 6 x 3 = 18
Then minus 18 from 21 to get $3
21 - 18 = 3