Alabama Instruments Company has set up a production line to manufacture a new calculator. The rate of  production of these calculators after t weeks is

(That production approaches 5000 per week as time goes on, but the initial production is lower because of the workers’ unfamiliarity with the new techniques.) Find the number of calculators produced from the beginning of the third week to the end of the fourth week.

dx 100 calculators/week 5000 1 dt (t + 10)