If A is thrice as fast as B and together can do a work in 18 days. In how many days A alone can do the work?
Choices.
A) 36  B) 42  C) 24  D) 54  E) 45
A’s one day’s work= 1/X   B’s one day’s work= 1/3x   A + B’s one day’s work= 1/x + 1/3x = 1/18   = 3+1/3x = 4/3x = 1/18   x = 18*4/3= 
<gadget id="calculator">18*4/3</gadget>
<output>24</output>
24   ANSWER:24
<result>C</result>
If A is thrice as fast as B and together can do a work in 18 days. In how many days A alone can do the work?