You can perform all kind of operation that are one the inverse of the other, so that the value won't change. For example, you can multiply and divide by 2:

Or add and subtract 5:

Answer:
Step-by-step explanation:
B) 36
To figure this out you need to average the numbers. To average them you add them all up and divide by how many are there.
(60+30+20)/3
(90+20)/3
110/3
36
Answer:
367
Step-by-step explanation:
because of PEMDAS, 3, 4, 5, and 6 have to be multiplied together, then 7 can be added later.

Carl needs to find the (B) Volume of the fish tank
Hope this helped!!