Rahul rented a power tool from a rental shop. The rent for the tool was $40 for the first hour and $20 for each additional hour. If Rahul paid a total of $160, excluding sales tax, to rent the tool, for how many hours did she rent it?	Choose the correct choice:
A) 1
B) 4
C) 9
D) 7
E) 3
40 + 20n = 160   n = 6   Total time = n+1 hrs = 6+1= 
<gadget id="calculator">6+1</gadget>
<output>7</output>
7 hrs   Answer : 7
<result>D</result>
Rahul rented a power tool from a rental shop. The rent for the tool was $40 for the first hour and $20 for each additional hour. If Rahul paid a total of $160, excluding sales tax, to rent the tool, for how many hours did she rent it?