a tank has 82 3/4 liters of water.24 4/5 liters were used and tha tank was filled with another 18 5/7 liters.what is the final volume in the tank

Question

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Answer 1

"a tank has 82 3/4 liters of water.24 4/5 liters were used"   means

      82  3/4

   -  24  4/5

 --------------

 

Let's convert the fractions so they have a common denominator:

      82  15/20

    - 24  16/20

  ----------------

 

We can subtract the whole numbers, but we have to "borrow one" so we can subtract the fractions:

      81  35/20

    - 24  16/20

  ----------------

      57  19/20           (notice how we had to "borrow one" here also)

 

Then, "tank was filled with another 18 5/7 liters"

 

      57  19/20

  +  18   5/7

 -----------------

 

Let's find common denominator again:

      57  133/140

   + 18  100/140

   ------------------

      75   233/140        [but, this is an improper fraction, so let's convert it]

      76    93/140 liters

Answer 2

82 3/4 - 24 4/5 + 18 5/7                           least common denominator is 140

82 105/140 - 24 112/140 + 18 100/140   combine first and third terms

100 205/140 - 24 112/140                       combine terms

76 93/140

 

The final volume in the tank is 76 93/140 L.