Question

The earned run average (ERA) a of a baseball pitcher varies directly as the number of earned runs r and inversely as the number of pitched innings p. In one season, a pitcher has an ERA of 2.475 with 80 innings pitched and 22 earned runs. Find the number of earned runs if the pitcher has an ERA of 2.25 after pitching 112 innings in the next season.

Find the number of earned runs when the pitcher has an ERA of 2.25 after pitching 112 innings in the next season.

Answer 1

The number of earned runs is 28.

Explanation:

Earned runs average:

The earned runs average of a pitcher is the number of runs the he/she gives each 9 innings on average.

Find the number of earned runs when the pitcher has an ERA of 2.25 after pitching 112 innings in the next season.

Solved by proportions, using a rule of three.

For each 9 innits, the pitcher gives 2.25 runs. How many runs for 112 innings?

9 innings - 2.25 runs

112 innings - x runs

Applying cross multiplication:

`9x = 2.25*112`

`x = (2.25*112)/(9)`

`x = 28`

The number of earned runs is 28.