Joseph's batting average after 9 innings (out every time) is 38. How many runs must he score in his 10th innings (and get out) to raise his average to 40?

Explanation

1. 01

   Runs so far = $9 \times 38 = 342$.

2. 02

   Runs needed after 10 innings = $10 \times 40 = 400$.

3. 03

   10th innings score = $400 - 342 = 58$.