Answer:
7.5 litres
Explanation:
Let the amount of orange juice ve 3x litres and amount of grapefruit juice be 1x. (As they are in ratio of 3:1.)
Now, according to the question,
- He makes 10 litres of the fruit drink.
So,
⇒ Amount of orange juice + Amount of grape fruit juice = 10 litres
⇒ 3x + x = 10
⇒ 4x = 10
⇒ x = 10 ÷ 4
⇒ x = 2.5
Now,
⇒ Amount of orange juice he used= 3x litres
⇒ Amount of orange juice he used= 3(2.5) litres
⇒ Amount of orange juice he used= 7.5 litres
∴ He used 7.5 litres of orange juice.