Before a salary increase, the weekly salary of a worker for 42 hours in a week was as much as the worker is paid now for 40 hours of work in a week. What is the percent increase in the worker's salary per hour? Choose the correct choice from the following options
A) 3 B) 4 C) 5 D) 6 E) 7
Let x be the original salary per hour.   Let y be the salary per hour after the increase.   40y=42x   y=(42/40)= 
<gadget id="calculator">(42/40)</gadget>
<output>21/20 = around 1.05</output>
1.05x   The salary increased 5%.   The answer is 5.
<result>C</result>
Before a salary increase, the weekly salary of a worker for 42 hours in a week was as much as the worker is paid now for 40 hours of work in a week. What is the percent increase in the worker's salary per hour?