At noon, an aquarium contained 20 gallons of water. After several hours, it contained

The tank decreased from 10cm to 7 cm so the tank had lost its 3cm of the water. 3cm was the 30% of lost from water. So there was a 30% decrease from water tank.

D

Step-by-step explanation:

Let's find A first.

Order of operations tells us that we need to simplify parentheses first.

( 25 x 4 ) ÷ 5 = A

Multiply out 25 x 4 in the parentheses

100 ÷ 5 = A

Dividing 100 by 5 gets us 20

So, A = 20

Now, let's find B

25 x 4 = B

This is even easier than the last one. Once again, we just multiply 25 by 4.

B = 100.

The next step is to find the relationship between the two.

If B is 100 and A is 20, then B is 5 times greater than A.

In other words, A is 5 times smaller than B.

So, the answer is D.