Question : A boat goes 2 km upstream and 3 km downstream in 20 minutes. It goes 7 km upstream and 2 km downstream in 53 minutes. What is the speed (in km/hr) of the boat in still water?

Option 1: $\frac{75}{7}$

Option 2: $\frac{120}{7}$

Option 3: $\frac{135}{7}$

Option 4: $\frac{150}{7}$

Question : A hollow cylindrical tube made of plastic is 3 cm thick. If the external diameter is 20 cm and the length of the tube is 49 cm, find the volume of the plastic.

Option 1: 7238 cm³

Option 2: 7644 cm³

Option 3: 7546 cm³

Option 4: 7854 cm³

Question : The volume of a solid right circular cone is $600 \pi \;\text{cm}^3$ and the diameter of its base is 30 cm. The total surface area (in cm²) of the cone is:

Option 1: $480 \pi$

Option 2: $255 \pi$

Option 3: $472 \pi$

Option 4: $496 \pi$

Question : The height of a cylinder is $\frac{2}{3}$rd of its diameter. Its volume is equal to the volume of a sphere whose radius is 4 cm. What is the curved surface area (in cm²) of the cylinder?

Option 1: $\frac{112}{3} \pi$

Option 2: $32 \pi$

Option 3: $\frac{128}{3} \pi$

Option 4: $40 \pi$

Question : 60 discs each of diameter 21 cm and thickness $\frac{1}{3}$ cm are stacked one above the other to form a right circular cylinder. What is its volume in m³ if $\pi=\frac{22}{7}$?

Option 1: 7.62 × 10^–2

Option 2: 8.05 × 10^–3

Option 3: 6.93 × 10^–3

Option 4: 4.25 × 10^–2