One percent

One percent of all the lights in the city are LED, and the remaining 99% are conventional. Other types are not there. John counted them honestly, but he had counted only conventional. After a good dinner, he registered numbers, and he gave notice that from all the lights in this city, he doesn't count LED contains 2%.

What percentage of lights in a city does John count?

Correct answer:

p =  50 %

Step-by-step explanation:

$$\begin{gathered} 0.01n/(n-p/100n)=0.02 \\ 0.01/(1-p/100)=0.02 \\ 1=2\cdot (1-p/100) \\ 0.5=p/100 \\ p=0.5\cdot 100=50\% \end{gathered}$$

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