The production of books in a publishing company went from 200 to 240 books per day. What is the percent increase in their production?

To calculate the percent increase in production, we first need to find the difference between the new production rate and the old production rate:

240 books per day - 200 books per day = 40 books per day

Next, we need to calculate the percent increase by dividing the difference by the old production rate and then multiplying by 100:

(40 books per day / 200 books per day) * 100 = 20%

Therefore, the percent increase in production is 20%.

Step 1: Calculate the difference in production

Difference = New production rate - Old production rate
Difference = 240 books/day - 200 books/day
Difference = 40 books/day

Step 2: Calculate the percent increase

Percent increase = (Difference / Old production rate) x 100%
Percent increase = (40 books/day / 200 books/day) x 100%
Percent increase = 20%

Therefore, the percent increase in their production is 20%.