The amount collected per month from a consumer of electrical power consists of two parts- a fixed charge for providing the service and a variable charge which is directly proportional to the number of units of power consumed. An amount of Rs. 700 is collected from the consumer when he consumed 50 units in a month. It is also noticed that when the consumption increases from 100 units per month to 200 units per month, the bill amount increases to 5/4 times that of the former. How much is the fixed charge per month?

Question

Explain how to do this. Please

Answer 1

Clearly, the fixed charge is always 700.

You must want the variable charge per unit. That means you want to solve

700+200x = 5/4(700+100x)

unless something else has been garbled.

Answer 2

Hello Steve

Can this be a possible way.

F + 100V = 4/5 (F + 200V)
By solving
F/V = 300
F/6 = 50V

F + 50V = 700
F + F/6 = 700
7F/6 = 700
F = 600

So, the fixed charge is 600

Answer 3

Ah, yes. You are correct. I had misread the problem.

Good work.

Answer 4

How did you get F/6=50V

Answer 5

If F=300v,
Then F/6=300v/6
F/6=50v