# CBSE Class 10-Mathematics: Chapter –13 Surface Areas and Volumes Part 18

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**Question 11:**

A cylindrical bucket, and high and with radius of base , is filled with sand. This bucket is emptied on the ground and a conical heap of sand is formed. If the height of the conical heap is , find the radius and slant height of the heap.

**Answer:**

For cylindrical bucket, Radius of the base

For conical heap, Height

Let the radius be .

Then, Volume

According to question, Volume of bucket Volume of conical heap

Now, Slant height

**Question 12:**

Water in a canal wide and deep is flowing with a speed of . How much area will it irrigate in minutes, if of standing water is needed?

**Answer:**

For canal, Width and Depth

Speed of flow of water

Speed of flow of water in minutes

Volume of water that flows in minutes

hectares hectares

**Question 13:**

A farmer connects a pipe of internal diameter from a canal into a cylindrical tank in her field, which is in diameter and deep. If water flows through the pipe at the rate of , in how much time will the tank be filled?

**Answer:**

For cylindrical tank, Diameter

Rate of flow of water

For pipe, Internal diameter , therefore radius

Volume of water that flows per minute

Required time