A can do a job in 10 days and B can do it in 30 days. A and B working together will finish twice the amount of work in ------- days? Choose the correct choice
A) 14 days	B) 15 days	C) 22 days	D) 11 days	E) 19 days
15 days   1/10 + 1/30 = 2/15   15/2 *2= 
<gadget id="calculator">15/2 *2</gadget>
<output>15</output>
15 days
<result>B</result>
A can do a job in 10 days and B can do it in 30 days. A and B working together will finish twice the amount of work in ------- days?