Question

Ritin has 21/5 litres of lemonade of which he distributed 13/4 litre lemonade . how much lemonade left with him

Answer 1

$\large\begin{array}{I} \mathtt{Lemonade~ left = \dfrac{21}{5} - \dfrac{13}{4} =\dfrac{21 \times 4 - 13 \times 5}{20} = \dfrac{84-65}{20}= \dfrac{19}{20}~ litres} \end{array}$

Answer 2

Ritin has 21/5 lemonade and he distributed meaning he took away 13/4 liters of lemonade. Find a common denominator  between 5 and 4. Since we know 5 times 4 is 20 the smallest common denominator so lets multiply 21/5 by 4 getting 84/20 and multiply 13/4 by 5 getting 65/20. Since both fractions have 20 as the denominator, subtract 84/20 by 65/20 and you get 19/20 liters of lemonade as your answer.
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Answer is 19/20 liters of lemonade Ritin has left