Question : The heights of two cones are in the ratio 7 : 5 and their diameters are in the ratio 10 : 21.
What is the ratio of their volumes? (Where $\pi=\frac{22}{7}$)

Question : The value of 5 ÷ [5 + 8 – {4 + (4 of 2 ÷ 4) – (2 ÷ 4 of 2)}] is:

Question : The volume of the two cones is in the ratio 1 : 4 and their diameters are in the ratio 4 : 5. The ratio of their height is:

Question : What is the positive value of the following expression?
$\sqrt{36 \div 15 \text { of } 2 \text { of }[25 \times 4 \div 4 \text { of }\{29-(8-11) \div(9 \times 5 \div 5 \text { of } 3)\}]}$

Question : In a mixture of 25 litres, the ratio of acid to water is 4 : 1. Another 3 litres of water is added. The ratio of acid to water in the new mixture is: