Answer:

Step-by-step explanation:
Given


Required
The cost of units used
First, calculate the number of units used.



Next, multiply the units used by the cost per units,
Since the cost per unit is not given, we assume that it is x.
So, the total cost is:



Answer:
31 u jest read it
Step-by-step explanation:
Answer:
7
Step-by-step explanation:
Answer:
There are multiple possibilities. One is there are 12 boys, and 16 girls. 12+16= 28 which is between 20 and 30. That would be 12:16, which can be simplified to 3:4. There is also 9 boys, and 12 girls. that would be 9:12, which can be simplified to 3:4. Also, 9 + 12 = 21, which is between 20 and 30.