A circular grassy plot of land, 42 in diameter has a path 3.5 m wide running around it on the outside. The cost of gravelling the path at Rs 4 per square meter is

Answer: B Required amount = pie (24.5<sup>2</sup> - 21<sup>2</sup>)*4 => Rs 2002.

Q. No. 14:

A plot of land in the form of a rectangle has dimension 240m x180m. A drainlet 10m wide is dug all around it (on the outside) and the earth dug out is evenly spread over the plot, increasing its surface level by 25 cm. The depth of the drainlet is

Answer: A Whole surface area = (2* 22/7 * 25/2 * 20) +(2* 22/7 * 23/2 * 20) => 3068 sq m.

Q. No. 16:

A metallic sheet is of rectangular shape with dimensions 48cm x 36cm. From each one of its corners, a square of 8 cm is cut off. An open box is made of the remaining sheet. Find the volume of the box.

Answer: C Volume of the box = 32*20*8 = 5120 sq cm.

Q. No. 17:

Consider the volumes of the following 1). A parallelopiped of length 5cm, breadth 3cm and height 4cm 2). A cube having each side 4 cm 3). A cylinder of radius 3cm and length 3 cm 4). A sphere of radius 3cm. The volumes of these in the decreasing order is

Answer: D Volume of parallelopiped = 5*4*3 = 60 cm^{3} Volume of cube = 4*4*4= 64 cm^{3} Volume of cylinder= pie *3*3*3 = 84.8 cm^{3} Volume of sphere= 4/3 * pie* 3*3*3 = 113 cm^{3}

Q. No. 18:

Four horses are tied on the four corners of a square field of 14 m length so that each horse can just touch the other two horses. They were able to graze in the area accessible to them for 11 days. For how many days is the ungrazed area sufficient for them?

Answer: A Total area of the square field = 14*14 = 196 sq m. Area grazed by four horses in 11 days = 4* pie/4 * 7*7 = 154 sq m. Ungrazed area = 196-154 = 42 sq m This area is sufficient for (11*42)/154 = 3 days.