Simplify 12a^{3}b^{2 }÷ 4ab^{−2}.

Orange juice concentrate is mixed with water in the ratio 2 : 5. This mixture is then mixed with lemonade in the ratio 3 : 4. What is the ratio of orange-juice concentrate to lemonade in the final mixture?

A triangle has side lengths in the ratio 3 : 4 : 5. If the perimeter of the triangle is 84 cm, what is the length of the shortest side

Jam is made from 4 parts fruit to 3 parts sugar. How much sugar is needed to make jam from 1kg of fruit?