A 2 kW heater, a 200 WTV and three 100W lamps are all switched on from 6 p.m. to 10 p.m. What is the total cost at Rs. 5.50 per kWh?

What is the cost of 27.5 m of cloth at Rs 53.50 per metre?

The sides of a triangular field are 140 m. 225m and 265 m . What is the cost of levelling it at Rs. 5.50 per m^(2) ?

An electric refrigerator rated 400 W and an electric bulb rated 100 W are operated 10 hours / day. What is the cost of the energy to operate them for 10 days at Rs. 8.00 per kWh ?

A farmer wants to fence his rectangular field of length 200 m and area 3000 m^2 . If the cost of fencing per metre is 5 rupees, what is the total cost of fencing in rupees?

An electric refrigerator rated 500 W operates 24 hours/day. What is the cost of the energy to operate it for 20 days at Rs.2.00 per kWh?

An electric refrigerator rated 400 W and an electric bulb rated 100 W are operate 10 hours/day . What is the cost of the energy to operate them for 10 days at ₹ 8.00 per kWh?

A metal block is placed in a room which is at 10^(@)C . It is heated by an electric heater of power 500 W till its temperature becomes 50^(@)C . Its initial rate of rise of temperature is 2.5^(@)C//sec . The heater is switched off and now a heater of 100 W is required to maintain the temperature of the block at 50^(@)C . (Assume Newtons Law of cooling to be valid) (i) What is the heat capacity of the block ? ( ii ) What is the rate of cooling of block at 50^(@)C if the 100W heater is also switched off ? (iii) What is the heat radiated per second when the block was 30^(@)C ?

A rectangular playground is 35 m long and 15 m broad. Find the cost of fencing it at Rs. 2.50 per metre.

Find the cost of laying grass in a triangular field of sides 50 m, 65 m and 65 m at the rate of Rs 7per m^2