Question

21. To find a baseball pitcher's earned run average (ERA), you can use the formula Ei=9r, in which E represents ERA, i represents the number of innings pitched, and r represents the number of eamed runs allowed. Please answer the following and separate your answers by a comma (EX: 10, 11) Solve the equation for E. What is the pitcher's ERA if he allows 5 earned runs in 18 innings pitched?

Answer 1

E = 2.5

Step-by-step explanation:

The initial eqauation is E=?r

To solve for E, we need to divide both sides by i as:

`\begin{gathered} E\cdot i=9\cdot r \\ (E\cdot i)/(i)=(9\cdot r)/(i) \\ E=(9\cdot r)/(i) \end{gathered}`

Now, to calculate the pitcher's ERA, we need to replace r by 5 earned runs and i by 18 innings pitched. Then:

`E=(9\cdot5)/(18)=2.5`

Therefore, the pitcher's ERA is equal to 2.5

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