Mathematics
The cross-section of a railway tunnel is a rectangle 6 m broad and 8 m high surmounted by a semi-circle as shown in the figure. The tunnel is 35 m long. Find the cost of plastering the internal surface of the tunnel (excluding the floor) at the rate of ₹ 2.25 per m2.
![The cross-section of a railway tunnel is a rectangle 6 m broad and 8 m high surmounted by a semi-circle as shown in the figure. The tunnel is 35 m long. Find the cost of plastering the internal surface of the tunnel (excluding the floor) at the rate of ₹ 2.25 per m<sup>2</sup>. Cylinder, Cone, Sphere, Concise Mathematics Solutions ICSE Class 10.](https://cdn1.knowledgeboat.com/img/cm10/q10-c20-ex-20-f-cylinder-cone-sphere-concise-maths-solutions-icse-class-10-282x392.png)
Mensuration
ICSE
3 Likes
Answer
Given,
Breadth of tunnel (b) = 6 m
Height of tunnel (h) = 8 m
Length of tunnel (l) = 35 m
Let radius of semi-circle be r meters.
From figure,
⇒ 2r = 6
⇒ r = 3 m.
Circumference of semi-circle = πr = m.
Internal surface area of tunnel = Circumference of semi-circle × Length + Area of side interior rectangular walls
= πrl + hl + hl
= πrl + 2hl
=
= 330 + 560
= 890 m2.
Given,
Rate of plastering = ₹ 2.25 per m2.
Total cost = 890 × ₹ 2.25 = ₹ 2002.50.
Hence, cost of plastering internal surface area of tunnel = ₹ 2002.50
Answered By
1 Like
Related Questions
The given figure shows the cross-section of a water channel consisting of a rectangle and a semi-circle. Assuming that the channel is always full, find the volume of water discharged through it in one minute if water is flowing at the rate of 20 cm per second. Give your answer in cubic meters correct to one place of decimal.
A cylindrical container with diameter of base 42 cm contains sufficient water to submerge a rectangular solid of iron with dimensions 22 cm × 14 cm × 10.5 cm. Find the rise in level of the water when the solid is submerged.
The horizontal cross-section of a water tank is in the shape of a rectangle with semi-circle at one end, as shown in the following figure. The water is 2.4 meters deep in the tank. Calculate the volume of water in the tank in gallons.
Given : 1 gallon = 4.5 litresSpherical marbles of diameter 1.4 cm are dropped into a beaker containing some water and are fully submerged. The diameter of the beaker is 7 cm. Find how many marbles have been dropped in it if the water rises by 5.6 cm?