A piece of work can be done by Ram and shyam in 12 days, By shyam Nad hari in 15 days and by hari and ram in 20 days. Ram alone can complete the work in how much days ?
Choose the correct option:
A) . 30
B) . 35
C) . 25
D) . 32
E) . 28
Rate*Time = Work   Since the work done is same throughout the question so we can take the work done as 1   Let Rate of Ram be R, Hari be H and Shaym be S   A piece of work can be done by Ram and shyam in 12 days   When Ram and Shyam will work together then their rate will be added. So combined rate will be R+S   (R+S)*12 = 1   R+S = 1/12 ...(1)   By shyam Nad hari in 15 days   Similarly   S+H = 1/15 ...(2)   hari and ram in 20 days   Similarly   H+R = 1/20 ...(3)   (2)-(3)   S+H - (H+R) = 1/15 - 1/20   =&gt; S-R = 1/60 ..(4)   (1) - (4)   R + S - (S - R) = 1/12 - 1/60 = 4/60 = 1/15   2R = 1/15 =&gt; R = 1/30   Ram alone can complet the work in how much days ?   R * t = 1   t = 1/R = 1/ (1/30)= 
<gadget id="calculator">1/ (1/30)</gadget>
<output>30</output>
30 days   So, . 30nswer will be . 30
<result>A</result>
A piece of work can be done by Ram and shyam in 12 days, By shyam Nad hari in 15 days and by hari and ram in 20 days. Ram alone can complete the work in how much days ?