Electricity consumption cost

Last year Karol family reduced its electricity consumption by 31% compared to the previous year and paid CZK 2883 less. How many CZK is electricity last year and how many two year ago?

Correct answer:

a =  6417
b =  9300

Step-by-step explanation:


a = b - 31/100 b
a = b - 2883

a = b - 31/100•b
a = b - 2883

100a-69b = 0
a-b = -2883

a = 6417
b = 9300

Our linear equations calculator calculates it.



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