A rain water tank is half full. After it rained the tank if four fifths full.

- Find the amount of water collected as a fraction of a full tank.

4/5 - 1/2 = 8/10 - 5/10

= 3/10 = fraction added by rain

The word half = 1/2.

Four fifths = 4/5.

To find the answer, we subtract 1/2 from 4/5.

Now:

1/2 = 50

4/5 = 80

80 - 50 = 30

30 = 3/10

Done!

help math

To find the amount of water collected as a fraction of a full tank, we can subtract the initial water level from the final water level and express it as a fraction of the full tank.

Given that the tank is initially half full, we can represent this as 1/2 (since half of a full tank is 1/2).

After it rained, the tank is four-fifths full. This can be represented as 4/5.

To find the amount of water collected, we subtract the initial water level (1/2) from the final water level (4/5):
4/5 - 1/2

To subtract fractions, we need a common denominator. In this case, the least common denominator is 10.

So, let's convert the fractions to have a common denominator of 10:
4/5 = 8/10 (multiply numerator and denominator by 2)
1/2 = 5/10 (multiply numerator and denominator by 5)

Now we can subtract the fractions:
8/10 - 5/10 = (8 - 5)/10 = 3/10

Therefore, the amount of water collected as a fraction of a full tank is 3/10.