Molly can do a task in 18 days while Sandy can do the task in 12 days. How many days will it take to complete the task if both work together?  Pick:
A) 6.2	B) 6.6	C) 7.2	D) 7.8	E) 8.4
Each day, Molly can do 1/18 of the task.   Each day, Sandy can do 1/12 of the task.   Each day, they can do 1/18 + 1/12 = 5/36 of the task.   The task will be completed in 36/5= 
<gadget id="calculator">36/5</gadget>
<output>36/5 = around 7.2</output>
7.2 days.   The answer is 7.8.
<result>D</result>
Molly can do a task in 18 days while Sandy can do the task in 12 days. How many days will it take to complete the task if both work together?