Molly can do a task in 10 days while Sandy can do the task in 30 days. How many days will it take to complete the task if both work together?
Select the correct option
A) 4.5	B) 6	C) 7.5	D) 8	E) 8.5
Each day, Molly can do 1/10 of the task.   Each day, Sandy can do 1/30 of the task.   Each day, they can do 1/10 + 1/30 = 2/15 of the task.   The task will be completed in 15/2= 
<gadget id="calculator">15/2</gadget>
<output>15/2 = around 7.5</output>
7.5 days.   The answer is 7.5.
<result>C</result>
Molly can do a task in 10 days while Sandy can do the task in 30 days. How many days will it take to complete the task if both work together?