Probability 63324

The shooter fired 100 times on the ground. He had four times more successful hits than failed hits. What was the probability of a hit in percent?

Correct answer:

p =  80 %

Step-by-step explanation:

$$\begin{gathered} n=100 \\ a+b=n \\ a=4b \\ a+b=100 \\ a=4b \\ a+b=100 \\ a=4\cdot b \\ a+b=100 \\ a-4b=0 \\ Row2-Row1\to Row2 \\ a+b=100 \\ -5b=-100 \\ b=\frac{-100}{-5}=20 \\ a=100-b=100-20=80 \\ a=80 \\ b=20 \\ p=100\cdot \frac{a}{n}=100\cdot \frac{80}{100}=\frac{100\cdot 80}{100}=\frac{8000}{100}=80\% \end{gathered}$$

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