In a household there are 4 CFL's of 15W each working for 5hrs a day, 2 fans of 60W working for 5hrs daily , 500Wiron box working for 15 minutes a day. How many units of electricity is used in this house . What is the cost of electricity costing 3 rupees per unit ?

In a house ,5 CF lamps each of 20 W, works for 4 hours, 4 fans each of 60 W work for 5 hours and a TV of 100W works for 4 hours in a day. What will be the daily composition shown by the watt hour meter ?

In a house 5 lamps of 60w used in 3 hours and 6 lamps of 40 w are used in 5 hours daily. Which is the device used to measure the used electric current?

A steam engine delivers 5.4×10^8 J of work per minute and services 3.6×10^9 J of heat per minute from its boiler.What is the efficiency of the engine?How much heat is wasted per minute?

In factory there are two machines A and B producing toys.They respectively produce 60 and 80 units in one hour.A can run a maximum of 10 hours and B a maximum of 7 hours a day .The cost of their running per hour respectively amount to 2,000 and 2,500 rupee.The total duration of working these machines cannot exceed 12 hours a day.If the total cost cannot exceed Rs. 25,000 per day and the total daily production is atleast 800 units,then formulate the problem mathematically.

A firm manufactures two types of products A and B and sells them at a profit of Rs. 5 per unit of type A and Rs. 3 per unit of type B . Each product is processed on two machines M_1 and M_2 . One unit of type A requires one minute of processing time, on, M_1 and two minutes of processing time on M_2 whereas one unit of type B requires one minute of processing time on M_1 and one minute of M_2 . Machines M_1 and M_2 are respectively available for at most 5 hours and 6 hours a day. Find how many, units of each type of product should the firm produce a day, in order, to maximise the profit. Solve thè problem graphically.

A factory makes tennis rackets and bats,A tennis racket takes 1.5 hours of machine and 3 hours of craftsman's time in its making,while a cricket bat takes 3 hours of machine time and 1 hour of craftman's time.In a day,the factory has availibilityof not more than 42 hours of machine time and 24 hours of craftman's time. What no of rackets and bats must be produced if the factory is to work at full capacity?

(Manufacturing problem) A manufacturer has three machines I , II and III installed in his factory. Machines I and II are capable of being operated for at most 12 hours where as machine III must be operated for atleast 5 hours a day. She produces only two items M and N each requiring the use of all the three machines. The number of hours required for producing 1 unit of each of M and N on the three machines are given in the following table: She makes a profit of Rs 600 and Rs 400 on items M and N respectively. How many of each item should she produce so as to maximise her profit assuming that she can swll all the items that she produced ? What will be the maximum profit ?

An electric heater calibrated 1.5 kW, 230 V is connected to a household branch circuit having 5A fuse wire and is made to work. What will happen ?

A bulb of 60W in a classroom remains switched on for a long time from 9 am to 5 pm due to the negligence of students in the class If similar negligence had happened in 3 clasrooms, how many units of electric energy would have been wasted ?