If A is thrice as fast as B and together can do a work in 30 days. In how many days A alone can do the work?	Answers.
A) 36
B) 42
C) 28
D) 54
E) 40
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 = 1/30   = 3+1/3x = 4/3x = 1/30   x = 30*4/3= 
<gadget id="calculator">30*4/3</gadget>
<output>40</output>
40   ANSW40R:40
<result>E</result>
If A is thrice as fast as B and together can do a work in 30 days. In how many days A alone can do the work?