Before lunch, a painter can paint a wall at a rate of r square feet per minute. The same painter, after lunch and a cup of coffee, can paint the same wall at a rate r + 1 square feet per minute, and the same wall would be finished in 30 seconds less time. What is the value of r? Choose one.
A) 1/3 B) 3 C) 1/2 D) 1 E) 2
Convert 30 seconds to 1/2 minute   Equation: 1/r = 1/(r + 1) + 1/2   Plug options into the equation:   1 fits:  1/1= 
<gadget id="calculator"> 1/1</gadget>
<output>1</output>
1/(1 + 1) + 1/2   Answer: 1
<result>D</result>
Before lunch, a painter can paint a wall at a rate of r square feet per minute. The same painter, after lunch and a cup of coffee, can paint the same wall at a rate r + 1 square feet per minute, and the same wall would be finished in 30 seconds less time. What is the value of r?