Pat, Kate, and Mark charged a total of 144 hours to a certain project. If Pat charged twice as much time to the project as Kate and 1/3 as much time as Mark, how many more hours did Mark charge to the project than Kate? Choices:  A) 18  B) 80  C) 72  D) 90  E) 108
80   all u do is do   2:1:6=&gt;2x+x+6x=144=&gt;x= 16   32:16:96   96-16= 
<gadget id="calculator">96-16</gadget>
<output>80</output>
80   Answer 80
<result>B</result>
Pat, Kate, and Mark charged a total of 144 hours to a certain project. If Pat charged twice as much time to the project as Kate and 1/3 as much time as Mark, how many more hours did Mark charge to the project than Kate?